Early life and career

Deng Ai was from Jiyang County (棘陽縣), Yiyang Commandery (義陽郡), which is around present-day Xinye County, Henan. He was born towards the end of the Eastern Han dynasty and lost his father at a young age. When the warlord Cao Cao conquered northern Jing Province in 208, Deng Ai moved to Runan Commandery (汝南郡; in present-day southern Henan), where he lived as a farmer and raised cattle. When he was 11 years old, he and his mother passed by Chen Shi's tomb in Yingchuan Commandery (潁川郡; around present-day Xuchang, Henan). He read two lines engraved on Chen Shi's tombstone: "his writings became examples of excellent prose; his conduct served as a role model for scholar-officials" (文為世範，行為士則). He was so inspired that he wanted to change his given name to Fan (literally "(role) model") and his courtesy name to Shize (literally "for scholar-officials to emulate"). However, since the names Fan and Shize were already used by members of his extended family, he could not change his names as such because it would violate naming taboo.

Deng Ai later became an academician under the Commandant of Xiangcheng (襄城; present-day Xiangcheng County, Henan). However, he was not too successful in his career because he stuttered in his speech. He then switched his job to an agricultural officer in charge of grain and fodder. The locals pitied him for his poor family background and often provided him with financial aid. Deng Ai initially did not show any form of gratitude towards them. Whenever he saw mountains and lakes, he started gesturing and pointing out how and where he believed army camps should be laid out, but was scorned by others. Later on, he was promoted to a clerical position which put him in charge of maintaining records of agricultural output.

Deng Ai had an acquaintance, Shi Bao (石苞), who was about the same age as him. They were quite close to Guo Xuanxin (郭玄信), who served as an Internuncio (謁者). When Ji Ben, an imperial physician, started a rebellion in Xu (許; present-day Xuchang, Henan) in 218, Guo Xuanxin was implicated and initially placed under house arrest until an officer came to escort him to the imperial capital for trial. Deng Ai and Shi Bao were among the escorts. While travelling for about ten li, Guo Xuanxin chatted with them along the way and remarked that the two of them would become very capable officials in the future. Deng Ai was later promoted to the rank of an Agricultural Officer of Merit (典農功曹).

Sometime between 235 and 239, he was sent as a messenger to the capital, Luoyang, where, by chance, he met Sima Yi, who was then serving as the Grand Commandant (太尉) under the Wei government. Sima Yi felt that Deng Ai was an extraordinary person so he recruited him and promoted him to the position of a Gentleman of Writing (尚書郎).

Agricultural and irrigation projects

Around the time, the Wei state was planning to promote agriculture and stockpile food resources in preparation for military campaigns against its rival states, Shu and Wu. Deng Ai was sent to survey the lands from the east of Chen and Xiang (項) commanderies (around present-day Zhoukou, Henan) to Shouchun (壽春; around present-day Shou County, Anhui), and assess their suitability for agriculture. He saw that the lands were fertile but lacked moisture, so they were not fully utilised. He suggested to dig irrigation channels to irrigate the land, and open up new canals for transporting goods by water.

Deng Ai wrote a proposal, the Ji He Lun (濟河論; Discussion on the River), to explain his ideas: Sima Yi agreed with Deng Ai's proposal and implemented his ideas.

In 241, the agricultural projects were complete. Whenever there were battles in the southeast between Wei and Wu, the Wei forces could sail down the river towards the Huai River region to counter the enemy. This was because they had plenty of food supplies stockpiled upstream and had the water pathways to their advantage. Deng Ai received credit for his proposal.

Battle of Tao River

Deng Ai later became a military adviser to the Wei general Guo Huai and served as the Administrator of Nan'an Commandery (南安郡; around present-day Longxi and Wushan counties, Gansu). In 249, he followed Guo Huai to resist an invasion led by the Shu general Jiang Wei. After the Shu forces were repelled, Guo Huai advanced west to attack the Qiang tribes. Deng Ai cautioned him: "The enemy did not retreat far. They might turn back to attack us again, so we should split up our forces in case they attack us again."

Deng Ai remained behind and garrisoned at the north of Baishui County. Three days later, Jiang Wei sent Liao Hua to lead a force to approach Deng Ai's camp from the south of Baishui. Deng Ai told his officers: "Jiang Wei has turned back to attack us. We have few troops. Ideally, we should cross the river and not build a bridge. I believe Jiang Wei must have sent Liao Hua to hinder us so that we are forced to remain here, while he would attack Taocheng (洮城) from the east." Taocheng was located north of the river and was about 60 li away from Deng Ai's position. Deng Ai immediately dispatched troops to travel overnight to Taocheng to defend the fortress. As he expected, Jiang Wei crossed the river to attack Taocheng, but failed to capture the fortress because Deng Ai had already strengthened its defences. For his achievements, Deng Ai was enfeoffed as a Secondary Marquis, awarded the rank of General Who Attacks Rebels, and subsequently appointed as the Administrator of Chengyang Commandery (城陽郡; around present-day Zhucheng, Shandong).

Advice on guarding against the Xiongnu

Around the time, the Xiongnu prince Liu Bao, who was nominally a vassal under the Wei government, was gradually building up his military forces in Bing Province. Deng Ai wrote a memorial to the Wei imperial court:

Deng Ai also suggested: "We should gradually segregate those Han Chinese living with barbarians, inculcate moral values such as integrity in them, so as to prevent them from resorting to unlawful actions." Sima Shi, the General-in-Chief who had recently taken over the reins of power as the regent of Wei, accepted Deng Ai's suggestions. He also appointed Deng Ai as the Administrator of Runan Commandery (汝南郡; in present-day southern Henan), where Deng lived in his younger days. Upon arriving in Runan to take office, Deng Ai sought a man who generously helped his father before because he wanted to repay that man for his kindness. However, he was disappointed to learn that the man had already died, so he sent his subordinates to pay respects at the man's tomb on his behalf. He also gave many gifts to the man's mother and recruited the man's son to be an accounting officer under him. During his tenure, Deng Ai developed wastelands in Runan and ensured that his soldiers and the common people had their basic needs fulfilled.

Giving advice to Sima Shi

When the Wu regent Zhuge Ke retreated after a failed attempt to capture the Wei-controlled fortress at Hefei, Deng Ai approached the Wei regent Sima Shi and said: As Deng Ai foresaw, Zhuge Ke was ousted from power not long after he returned to Wu and was killed along with his family.

Deng Ai was appointed as the Inspector of Yan Province (兖州刺史) and promoted to General Who Inspires Might. He wrote a memorial to the Wei imperial court:

Helping to suppress the second Shouchun rebellion

Deng Ai was enfeoffed as the Marquis of Fangcheng Village (方城亭侯) after Cao Mao became the new Wei emperor in 254. In the following year, when the Wei generals Guanqiu Jian and Wen Qin started a rebellion in Shouchun (壽春; around present-day Shou County, Anhui), they sent messengers to other areas to incite the people to join their rebellion. Deng Ai arrested and executed the messengers, and then led troops to suppress the rebellion. His force occupied Yuejia (樂嘉; present-day Xiangcheng, Henan) and started building pontoon bridges. When the main Wei army led by Sima Shi showed up, Deng Ai rendezvoused with him and they advanced towards Shouchun together. The rebels were subsequently defeated. Deng Ai pursued the fleeing Wen Qin to Qiutou (丘頭; southeast of present-day Shenqiu County, Henan), but Wen Qin still managed to escape and defect to Wei's rival state, Wu.

The Wu general Sun Jun led thousands of troops and crossed the Yangtze to support the rebels. The Wei general Zhuge Dan ordered Deng Ai to resist the enemy at Feiyang (肥陽), but Deng saw that if he was stationed in Feiyang he would be in a disadvantageous position, so he relocated his troops to a neighbouring village. He then sent Zhuge Xu to attack the remaining rebels and Wu forces at Lijiang Village (黎漿亭; southeast of present-day Shou County, Anhui), where they defeated the enemy.

In the same year, Deng Ai was promoted to Colonel of Changshui (長水校尉). Later on, for his contributions in suppressing the rebellion, he was further promoted to acting General Who Stabilises the West and his marquis rank was increased by one grade to Marquis of Fangcheng District.

Battles against Shu

Around 255, the Shu general Jiang Wei led forces to attack Wei and besieged Wang Jing, the Inspector of Yong Province, in Didao (狄道; southwest of present-day Lintao County, Gansu). The Wei imperial court appointed Deng Ai as General Who Stabilises the West and Colonel Who Protects the Eastern Qiang to lead troops to lift the siege. By then, Jiang Wei had withdrawn to Zhongti (鍾提; south of present-day Lintao County, Gansu), so many of Deng Ai's subordinates thought that Jiang Wei was exhausted and would not attack Didao again. However, Deng Ai held a different opinion and he said: As Deng Ai predicted, Jiang Wei led his forces to attack Mount Qi later but were repelled by the defences set up by Deng. Jiang Wei retreated to Dong Village (董亭; south of present-day Wushan County, Gansu), while Deng Ai stationed his troops at Mount Wucheng (武城山). Jiang Wei tried to seize control of the mountainous terrain from Deng Ai, but was driven back. That night, Jiang Wei attempted to cross the Wei River to attack Shanggui (上邽; present-day Tianshui, Gansu). Deng Ai intercepted Jiang Wei at Duan Valley (段谷; southwest of present-day Tianshui, Gansu) and defeated him.

In 256, the Wei imperial court issued an edict as follows:

In the following year, Deng Ai defeated Jiang Wei in battle again along the Great Wall and forced him to retreat back to Shu. He was further promoted to General Who Attacks the West, and had the number of taxable households in his marquisate increased to 6,600. In 262, he defeated Jiang Wei in battle at Houhe (侯和). Jiang Wei retreated to Tazhong (沓中; northwest of present-day Zhugqu County, Gansu) and garrisoned there.

Conquest of Shu by Wei

Strategic planning and opening moves

In the autumn of 263, the Wei imperial government started mobilising troops in preparation for a campaign against Shu. Sima Zhao, who oversaw the campaign, ordered Deng Ai to lead 30,000 troops to Tazhong (沓中; northwest of present-day Zhugqu County, Gansu) to harass Jiang Wei and keep him occupied, while Zhuge Xu, the Inspector of Yong Province, would lead forces to block Jiang Wei's retreat route back to Shu. Before Deng Ai embarked on the campaign against Shu, he dreamt of himself sitting on a mountaintop with water flowing near him. He asked an official, Yuan Shao (爰邵), who was well-versed in the Yijing, to explain to him what his dream meant. Yuan Shao told him that he would successfully conquer Shu, but would not return to Wei. Deng Ai felt gloomy after hearing this.

Deng Ai sent Wang Qi (王頎) to lead troops attack Jiang Wei's camp directly, with Qian Hong leading another force to clear the path, and Yang Xin to attack the enemy positions at Gansong (甘松; around present-day Songpan County, Sichuan).

When Jiang Wei received news that another Wei army led by Zhong Hui had occupied Hanzhong Commandery, he led his troops from Tazhong back further into Shu territory, but was pursued by Yang Xin to Qiangchuankou (彊川口; the intersection of the Bailong and Jialing rivers), where he was defeated. Jiang Wei learnt that Zhuge Xu had blocked his retreat route at the bridge of Yinping, so he led his men through Konghan Valley (孔函谷; south of present-day Xigu District, Lanzhou, Gansu) to the northern road in an attempt to bypass Zhuge Xu's position. When Zhuge Xu heard about it, he retreated back by 30 li. By then, Jiang Wei and his troops had travelled about 30 li on the northern road when they heard that Zhuge Xu had lifted the blockade at the bridge. Jiang Wei ordered his troops to quickly turn back and cross the bridge. Zhuge Xu tried to turn back to block Jiang Wei again but arrived at the bridge one day too late. After crossing the bridge, Jiang Wei moved to the mountain pass of Jiange and garrisoned there. Zhong Hui attacked Jiang Wei at Jiange several times but was unable to breach the defences.

Capture of the Shu capital

Deng Ai proposed:

Zhong Hui approved Deng Ai's idea and even ordered his subordinate Tian Zhang (田章) to join Deng Ai on the expedition. Some time between 18 November and 17 December 263, Deng Ai led a strike force from Yinping through the shortcut, bypassing the west of Jiange and heading straight towards Jiangyou. The shortcut covered a distance of more than 700 li and cut across mountainous terrain. Deng Ai and his men had to construct several bridges along the way. The mountains were high and the valleys were deep, which made the journey extremely dangerous. After some time, they were completely cut off from their supply train. Deng Ai wrapped himself in a large piece of felt and rolled down the mountain. His men climbed trees and scaled cliffs in single file. Along the way, they encountered three groups of Shu ambushers, defeated them and destroyed their camps. Deng Ai let Tian Zhang lead the vanguard and clear the path. Deng Ai and his vanguard showed up at Jiangyou. Ma Miao, the Shu-appointed administrator of Jiangyou, gave up resistance and surrendered to Deng Ai.

The Shu general Zhuge Zhan led an army from Fu County to Mianzhu, where they engaged Deng Ai and his troops in battle. Deng Ai ordered his son Deng Zhong (鄧忠) to flank the enemy from the right, and Shi Zuan (師纂) to flank the enemy from the left. Both Deng Zhong and Shi Zuan were driven back by Zhuge Zhan, and they told Deng Ai: "The enemy cannot be defeated.". Deng Ai sternly replied: "This battle will determine whether we live or die. What do you mean when you say the enemy cannot be defeated?" He wanted to execute them, but they turned back and hastily readied their troops for battle again. They defeated the Shu forces and killed the enemy officers Zhuge Zhan, Zhuge Shang and Zhang Zun.

Deng Ai and his men then pressed on further to Luo County (雒縣; north of present-day Guanghan, Sichuan). Liu Shan, the Shu emperor, sent an emissary to present his imperial seal to Deng Ai and indicate his wish to surrender.

Managing post-war Shu

When Deng Ai arrived in Chengdu, Liu Shan tied himself up and led an entourage of over 60 people to officially surrender. Deng Ai freed Liu Shan from his bonds and treated him kindly. He also forbid his soldiers from plundering and pillaging the city, and ordered that daily activities in the city resume as per normal. Many former Shu officials were so impressed with Deng Ai that they willingly submitted to him; the people of Shu also praised Deng Ai for his kindness. Deng Ai used his acting imperial authority granted by the Wei government to appoint Liu Shan as acting General of Chariots of Cavalry and grant titles to many former Shu nobles and officials; some of them became his subordinates. Deng Ai also appointed Shi Zuan as the Inspector of Yi Province and put Qian Hong in charge of overseeing the former Shu commanderies. A memorial was constructed at Mianzhu to glorify Deng Ai's victory over Zhuge Zhan, and the fallen Wei soldiers were buried alongside their Shu counterparts.

Deng Ai became arrogant about his achievements in conquering Shu. He once bragged to the former Shu officials: "All of you are lucky to have encountered me, which is why you are where you are today. If you encountered someone like Wu Han, you would have been destroyed." He also said: "Jiang Wei is a short-lived hero. He pales in comparison with me." Some people scorned him for his boastfulness.

On 8 February 264, the Wei imperial court issued an edict praising Deng Ai for his successful conquest of Shu and comparing him to famous generals such as Bai Qi, Han Xin, Wu Han and Zhou Yafu. Deng Ai was promoted to the position of Grand Commandant (太尉) in the imperial court and had the number of taxable households in his marquisate increased by 20,000. His two sons were made village marquises (亭侯) and given 1,000 taxable households each in their marquisates.

Downfall and death

Correspondence between Deng Ai and Sima Zhao

Deng Ai wrote to Sima Zhao, suggesting that they let the weary troops rest and recuperate while concurrently making preparations for a future campaign against Wei's other rival state, Wu. He also proposed that Liu Shan be treated generously by making him a prince and showering him with luxuries. The purpose of doing so was to induce and tempt Sun Xiu, the Wu emperor, into voluntarily surrendering to Wei. He wrote:

Sima Zhao sent Wei Guan to reply Deng Ai that his proposal would be submitted to the Wei imperial court for further deliberation before it could be implemented. Deng Ai grew impatient and argued that they would be wasting time if they had to wait for further instructions from the imperial court before taking action. He quoted lines from the Spring and Autumn Annals and The Art of War to hint that he was justified in ignoring standard protocol and acting autocratically as long as what he did was to Wei's benefit. He wrote:

Zhong Huis role in Deng Ais arrest

Zhong Hui, Hu Lie (胡烈), Shi Zuan (師纂) and others accused Deng Ai of showing disrespect for the Wei imperial court's authority, and claimed that he was likely to start a rebellion. The Shiyu mentioned that Zhong Hui was skilled in imitating people's handwriting. After getting his hands on a letter written by Deng Ai to Sima Zhao, he edited it to make it sound arrogant and demanding. At the same time, he also destroyed a letter from Sima Zhao to Deng Ai to increase Sima's suspicions towards Deng.

Sometime in late February 264, the Wei imperial court then issued an edict ordering Deng Ai to be arrested and transported back to the capital, Luoyang. Wei Guan and Zhong Hui went to Deng Ai's camp, where they used Sima Zhao's letter to order Deng Ai's men to put down their weapons. Deng Ai was arrested and placed in a prison cart for his journey to Luoyang. When he was arrested, Deng Ai exclaimed: "I am a loyal subject, yet I meet with such a fate! Whatever that happened to Bai Qi in the past has just happened to me in the present."

Death

After Deng Ai was escorted away, Zhong Hui started a rebellion against Wei in Chengdu on 1 March 264, but the rebellion failed when some Wei officers, who were unwilling to participate, mutinied against Zhong Hui and killed him on 3 March 264. After Zhong Hui's death, Deng Ai's subordinates caught up with the convoy escorting their general, freed him, and brought him back to Chengdu. When Wei Guan heard about it, he ordered Tian Xu to lead troops to attack Deng Ai.

Tian Xu had initially served under Deng Ai during the campaign against Shu. During an earlier battle at Jiangyou, Deng Ai wanted to execute Tian Xu for delaying his advance against the enemy, but spared him eventually. When Wei Guan sent Tian Xu to attack Deng Ai, he told Tian, "You can now take revenge against Deng Ai for how he humiliated you at Jiangyou."

Tian Xu and his soldiers intercepted Deng Ai at the west of Mianzhu and killed him along with his son, Deng Zhong (鄧忠), and Shi Zuan. After Deng Ai's death, his other son(s) in Luoyang was/were also rounded up and executed, while his surviving family members were exiled to the Western Regions.

When the Wei general Du Yu heard about what Wei Guan told Tian Xu, he remarked that Wei Guan, as a man of high social status, should not behave in such a petty and spiteful manner. When Wei Guan heard about Du Yu's remarks, he immediately went to meet Du Yu to thank him.

Posthumous rehabilitation and legacy

In 265, after the Jin dynasty replaced the Wei regime, Sima Yan (Emperor Wu) issued an imperial edict to pardon Deng Ai's descendants and allow them to return from exile. He noted that Deng Ai was fairly punished for his arrogance and audacity, but the "redeeming" factor was that Deng Ai did not resist arrest and willingly resigned to his fate.

When Deng Ai was stationed in Yong and Liang provinces, he strengthened the parapets in the area and had some forts constructed for defensive purposes. During the mid-Taishi era (265–274) in Emperor Wu's reign, the Qiang tribes in Yong Province rebelled against Jin rule and killed the Inspector of Liang Province. The surviving officials and local residents found safety in the forts built by Deng Ai about a decade earlier.

Family and descendants

Deng Ai had at least two sons. Two of his sons – one of whom was Deng Zhong (鄧忠) – held village marquis titles and owned marquisates of 1,000 taxable households. Deng Zhong was killed along with his father. Deng Ai's other sons who were in Luoyang were arrested and executed in the aftermath of their father's death. Deng Ai's surviving family members were exiled and allowed to return only in 265 after Emperor Wu of the Jin dynasty issued an imperial edict pardoning them.

In 273, Emperor Wu appointed Deng Ai's grandson, Deng Lang (鄧朗), as a langzhong (郎中). Deng Lang served as the Prefect of Danshui County (丹水縣; around present-day Xichuan County, Henan) and then as the Prefect of Dingling County (定陵縣; around present-day Qingyang County, Anhui). He had at least one son, Deng Tao (鄧韜). During the Yongjia era (307–313) in the reign of Emperor Huai, Deng Lang was appointed as the Administrator of Xindu Commandery (新都郡; around present-day Guanghan, Sichuan). However, before he left to assume office, he died in a fire in Xiangyang Commandery along with his mother, wife and children. Only his grandson Deng Xing (鄧行), Deng Tao's son, survived the fire.

Deng Qianqiu (鄧千秋), another grandson of Deng Ai, was recruited to serve under Wang Rong, a prominent Jin dynasty official. He died before Deng Lang while his two sons also perished in the Xiangyang fire.

Appraisal

Chen Shou (233–297), who wrote Deng Ai's biography in the Sanguozhi, commented on Deng Ai as follows: "Deng Ai was upright and strong. He achieved many successes, but failed to protect himself from hidden pitfalls and dangers, which resulted in his eventual downfall. He could envision what would happen to Zhuge Ke, yet ironically could not foresee his own fate. This was probably what the ancients called 'lack of self-awareness and narrow-mindedness'."

In 267, Duan Zhuo (段灼) wrote a memorial to Emperor Wu of the Jin dynasty to speak up for Deng Ai. In the memorial, Duan Zhuo discussed Deng Ai's contributions to Wei and argued that Deng had no intention of rebelling against Wei. He also mentioned that Deng Ai had been deeply misunderstood because of his boorish and uncouth behaviour, which made him likely to offend people easily. Duan Zhuo also compared Deng Ai to Bai Qi and Wu Zixu, two generals in the Spring and Autumn period who made great contributions to their respective states but were forced to commit suicide.

During the mid-Xianning era (275–280) in Emperor Wu's reign, Fan Zhen (樊震), a general who previously served under Deng Ai during the Wei campaign against Shu, had an audience with the emperor. When Emperor Wu asked about Deng Ai, Fan Zhen became very emotional and he recalled that Deng Ai was a very loyal subject to Wei.

In popular culture

Deng Ai is first introduced as a playable character in the seventh instalment of Koei's Dynasty Warriors video game series. In the game, he is erroneously associated with the Jin dynasty faction; historically, he died one year before the Jin dynasty was established.

生平

早年

鄧艾早年喪父，家境清寒，長期居於今河南省境內。鄧艾自小已有口吃毛病；曾於汝南（今河南上蔡）牧牛一時。12歲隨母遷居潁川時，見到已故太丘長陳寔碑文上寫著「文為世範、行為士則」，便自行取名為鄧範，字士則。後來有一個族人跟他同名，遂改為鄧艾。

鄧艾早年憑其才學獲舉薦為典農都尉，然而因為口吃未能遷陞，因而就任與農業相關的稻田守叢草吏一職。鄧艾酷愛軍事，每到高山大澤，定必測量繪製地形，規劃紮營佈防。時人常取笑鄧艾，然鄧艾並不在意。

積糧墾荒

鄧艾在地方任職十數年後，擔任上計吏，前往京都洛陽向太尉司馬懿匯報地方工作時，因司馬懿賞識，鄧艾總算被提拔，成為太尉府掾屬；後升任尚書郎。

由正始元年（240年）起，魏國準備在淮河兩岸展開大規模屯田，以積備軍糧。鄧艾獲派往視察，及後還著《濟河論》以闡明具體方案。他認為：「昔破黃巾，因為屯田，積穀于許都以制四方。今三隅已定，事在淮南，每大軍征舉，運兵過半，功費巨億，以為大役。陳、蔡之間，土下田良，可省許昌左右諸稻田，並水東下。令淮北屯二萬人，淮南三萬人，十二分休，常有四萬人，且田且守。水豐常收三倍于西，計除眾費，歲完五百萬斛以為軍資。六七年間，可積三千萬斛于淮上，此則十萬之眾五年食也。以此乘吳，無往而不克矣。」

司馬懿對此非常滿意，決定採納施行，由黃河引水注入兩淮，並在兩淮每五里設一軍屯營，每營六十人，為穩定東南形勢，提供堅實的後勤保障。

251年司馬懿去世，由長子司馬師繼承父職。鄧艾先任汝南太守，後又任兗州刺史，加振威將軍。鄧艾每到一處就屯田墾荒，「艾所在，荒野開闢，軍民並豐」。

曲城之戰

249年秋，蜀國姜維出師進攻雍州（今陝西關中及甘肅東部），欲拉攏羌胡歸蜀。司馬昭派郭淮、陳泰統兵抵禦，鄧艾也參與其中。鄧艾進圍曲城（今甘肅岷縣東百里），切斷交通及水源，曲城蜀軍困窘不堪。姜維迅速撤回。魏國把鄧艾留守白水(今甘肅白龍江)北岸屯兵，以防蜀軍反攻。不久姜維派廖化率兵復返，在白水南岸扎營，與鄧艾對峙。鄧艾分析姜維在派廖化駐守白水南岸時，欲從北面洮城（今甘肅臨潭西南）偷襲。鄧艾乃即時搶佔洮城。後姜維果然率兵攻洮城，見鄧艾搶先一步，只好撤軍，魏兵得以不敗。鄧艾因此功被賜爵關內侯，加討寇將軍。

254年曹髦即位，鄧艾進爵方城亭侯，後參與鎮壓毌丘儉之亂，因此又進封方城鄉侯，行安西將軍。

狄道之戰

正元二年（255年）司馬師病危，蜀國姜維乘機派數萬人伐魏，進攻隴西，向狄道（今甘肅臨洮）進軍。魏將陳泰死命抵抗，仍被姜維成功包圍狄道。同年八月辛未日（10月9日），司馬昭命鄧艾出任安西將軍、假節、領護東羌校尉，跟陳泰等並力抗蜀。陳泰與鄧艾軍會合後，分三路進至隴西，避開蜀軍，出其不意地繞過高城嶺（今甘肅渭源西北），進至狄道東南山上，燃火擊鼓與城內聯絡，守軍見援軍至，士氣大振。姜維即督軍沿山進攻，被魏軍擊退。這時陳泰揚言截斷蜀軍退路，九月甲辰日（11月11日），姜維遂撤軍退走鐘堤（今甘肅臨洮南）。

段谷之戰

255年姜維伐魏失敗，退守鍾堤。鄧艾認為姜維會再次來犯，所以加緊防備。256年，六月，姜維與蜀將胡濟約定在上邽（今甘肅天水）會合。姜維率先出兵祁山，鄧艾有備，乃改從董亭（今甘肅武山南）攻南安（今甘肅隴西東南）。鄧艾軍搶佔武城山（今甘肅武山西南）據險拒守。姜維見地利已失，強攻難克，於是夜渡渭水東進，沿山進取上邽。兩軍戰於段穀（今甘肅天水西南）。胡濟失期未至，蜀軍交戰不利，死傷甚眾。魏國因此封鄧艾為鎮西將軍、都督隴右諸軍事，進封鄧侯，分五百戶，封子鄧忠為亭侯。

不戰而勝

257年魏將諸葛誕聯合東吳在淮南起兵反司馬昭。司馬昭調關中兵力東下討伐諸葛誕。姜維乘機攻魏秦川（渭水流域）。當時魏在長城（今陝西周至南）積存大量軍糧，但防守薄弱。鄧艾與魏將司馬望恐姜維襲奪長城，立即合軍據守。姜維軍進至芒水（今陝西周至黑水），依山為營。司馬望、鄧艾軍近水築寨。蜀軍多次挑戰，魏軍堅守不出，兩軍長期對峙。次年（258年）諸葛誕敗亡，姜維聞訊，只得引軍而還。鄧艾不戰而勝，因而再升任征西將軍，前後共增食邑六千六百戶。

262年姜維再起兵伐魏，攻入洮陽境。鄧艾抓住姜維懸師遠征，戰線長，給養困難，難以持久的弱點，搶佔有利地勢，在洮陽以東的侯和（今卓尼東北）設陣，以逸待勞，阻擊蜀軍。雙方激戰後，鄧艾發起反擊，蜀軍大敗，損失嚴重。

偷渡陰平

263年秋，大將軍司馬昭策劃大舉伐漢，命鄧艾率三萬餘人糾纏屯田沓中的姜維，雍州刺史諸葛緒率三萬餘人斷其歸路，鍾會統十餘萬眾進攻漢中，廷尉衛瓘監軍。鐘會攻破漢中，姜維退守劍閣，相持不下。十月，鄧艾挑選精銳，從陰平小路無人之地隱蔽前進。山高谷深，糧食將盡，在生死存亡的緊急關頭，鄧艾用毛氈裹住自己，翻滾著下山，于是將士們也都攀緣山崖樹木，魚貫而進。奇兵出現在江油，蜀漢守將馬邈投降。鄧艾率軍迅速攻破涪陵及綿竹，蜀漢衛將軍、諸葛亮之子諸葛瞻戰死。不久，劉禪投降，蜀漢滅亡，之後鄧艾在綿竹修築京觀。

功高自傲

伐蜀勝利之後，鄧艾擅自拜劉禪為驃騎將軍，恢復其它蜀國官員的職位，重操舊職。他曾對蜀國的官員說：「諸位因為有我，所以才有今天。如果你們碰到吳漢這樣的人，你們早已滅亡。」又說：「姜維只不過一時的英雄而已，與我相遇，所以窮途末路。」向來與其不睦的鐘會藉此向司馬昭誣稱鄧艾謀反，而鄧艾在處置投降的蜀漢君臣時沒有遵從司馬昭的指示，也加深司馬昭的疑忌，遂命鐘會收捕鄧艾送長安。鐘會謀反失敗被誅後，鄧艾部將欲追還鄧艾，衛瓘為了自身安危，派遣田續在綿陽西殺死鄧艾、鄧忠父子。鄧艾在洛陽的諸子也被殺。泰始九年（273年），晉武帝司馬炎下詔「艾有功勳，受罪不逃刑，而子孫為民隸，朕常愍之」，遂拔擢其孫鄧朗為郎中。

軼事

• 諸葛恪包圍合肥新城不成而撤退，當時鄧艾向司馬師預測說諸葛恪會身亡名裂，果然諸葛恪最後被孫峻誣陷身亡，但沒想到自身在十年後歷史重演，也為鐘會等人陷害身亡。

• 鄧艾出兵蜀漢前，曾夢見自己席坐於山上，眺望著流水，於是找來殄虜護軍爰邵，問夢境的暗示。爰邵以「即使能取勝蜀漢，恐怕將軍也難以返國」相告，後來果然一如所料。

• 《世說新語·言語篇》中有一則關於鄧艾機敏的故事，記曰鄧艾有口吃，每次說話提到自己時老是「艾、艾」連呼，司馬昭故意戲弄他，便問：「你老是說『艾、艾』，究竟有多少個『艾』啊？」鄧艾回答：「楚狂接輿曾在孔子旁唱道『鳳兮鳳兮』，其實只有一鳳而已啊。」(原文：鄧艾口吃，語稱「艾艾……」晉文王戲之曰：「卿雲『艾艾』，定是幾艾？」對曰：「『鳳兮鳳兮』，故是一鳳。」)。此與西漢有口吃的周昌被後世結合為成語「期期艾艾」。

• 唐代李翰所撰《蒙求》中有「鄧艾大志」一語。

• 前蜀天漢元年（917年）（其時國號為漢）正月追封鄧艾為彰順王。

• 宋代歐陽修、宋祁等撰寫的《新唐書·卷十五·志第五·禮樂五·吉禮五》中提到，唐代時禮儀使顏真卿曾經向皇室建議，追封古代名將六十四人，並為他們設廟享奠，當中就包括「魏太尉鄧艾」。同時代被列入廟享名單的只有張遼、關羽、張飛、周瑜、呂蒙、陸遜、陸抗、羊祜而已。

• 同樣，元代脫脫等撰寫的《宋史·卷一零五·志第五十八·禮八·吉禮八》提及宋代宣和五年時，皇室依照唐代慣例，為古代名將設廟，七十二位名將中亦包括鄧艾。

• 中國河南省周口市商水縣有一道「鄧城豬蹄」，據稱是鄧艾於此地駐屯時，由軍中廚子烹調的菜餚，名傳至今。

評價

• 曹髦：「逆賊姜維連年狡黠，民夷騷動，西土不寧。艾籌畫有方，忠勇奮發，斬將十數，馘首千計；國威震於巴、蜀，武聲揚於江、岷。」（《三國志·王毌丘諸葛鄧鍾傳》）

• 曹奐：「艾曜威奮武，深入虜庭，斬將搴旗，梟其鯨鯢，使僭號之主，稽首系頸，歷世逋誅，一朝而平。兵不逾時，戰不終日，雲徹席捲，盪定巴蜀。雖白起破強楚，韓信克勁趙，吳漢禽子陽，亞夫滅七國，計功論美，不足比勛也。」（《三國志·王毌丘諸葛鄧鍾傳》）

• 司馬炎：「征西將軍鄧艾，矜功失節，實應大闢。然被書之日，罷遣人眾，束手受罪，比於求生遂為惡者，誠復不同。」「艾有功勳，受罪不逃刑，而子孫為民隸，朕常愍之。」（《三國志·王毌丘諸葛鄧鍾傳》）

• 陳壽：「鄧艾矯然強壯，立功立事，然闇於防患，咎敗旋至，豈遠知乎諸葛恪而不能近自見，此蓋古人所謂目論者也。」「艾所在，荒野開闢，軍民並豐。」（《三國志·王毌丘諸葛鄧鍾傳》）

• 段灼：「艾心懷至忠而荷反逆之名，平定巴蜀而受夷滅之誅，臣竊悼之。惜哉，言艾之反也！艾性剛急，輕犯雅俗，不能協同朋類，故莫肯理之……昔姜維有斷隴右之志，艾脩治備守，積穀強兵。值歲凶旱，艾為區種，身被烏衣，手執耒耜，以率將士。上下相感，莫不儘力。艾持節守邊，所統萬數，而不難僕虜之勞，士民之役，非執節忠勤，孰能若此？故落門、段谷之戰，以少擊多，摧破強賊。先帝知其可任，委艾廟勝，授以長策。艾受命忘身，束馬縣車，自投死地，勇氣陵雲，士眾乘勢，使劉禪君臣面縛，叉手屈膝。艾功名以成，當書之竹帛，傳祚萬世。七十老公，反欲何求！艾誠恃養育之恩，心不自疑，矯命承制，權安社稷；雖違常科，有合古義，原心定罪，本在可論……忠而受誅，信而見疑，頭縣馬巿，諸子並斬，見之者垂泣，聞之者嘆息……今天下民人為艾悼心痛恨，亦猶是也。」（《三國志·王毌丘諸葛鄧鍾傳》）

• 唐彬：「鄧艾忌克詭狹，矜能負才，順從者謂為見事，直言者謂之觸迕。雖長史司馬，參佐牙門，答對失指，輒見罵辱。處身無禮，大失人心。又好施行事役，數勞眾力。隴右甚患苦之，喜聞其禍，不肯為用。」（《晉書·唐彬傳》）

• 袁准：「今國家一舉而滅蜀，自征伐之功，未有如此之速者也。方鄧艾以萬人入江由之危險，鐘會以二十萬眾留劍閣而不得進，三軍之士已飢，艾雖戰勝克將，使劉禪數日不降，則二將之軍難以反矣。故功業如此之難也。國家前有壽春之役，後有滅蜀之勞，百姓貧而倉稟虛，故小國之慮，在于時立功以自存，大國之慮，在于既勝而力竭，成功之後，戒懼之時也。」

• 虞預：「王基、鄧艾、周秦、賈越之徒，皆起自寒門，而著績于朝。」

• 王安石：「昔鄧艾不賴蔡河漕運，故能並水東下，大興水田。」（《宋史·河渠志》）

• 梁周瀚：「亞夫則死於獄吏，鄧艾則追於檻車……凡此名將，悉皆人雄，苟欲指瑕，誰當無累，或從澄汰，盡可棄捐。」（《宋史·梁周瀚傳》）

• 尉元：「進無鄧艾一舉之功，退無羊祜保境之略。」（《魏書·尉元傳》）

• 成淹：「至如鄧艾懷忠，矯命寧國，赤心皎然，幽顯同見，而橫受屠戮，良可悲哀。」（《魏書·慕容白曜傳》）

• 李商隱：「或謔張飛胡，或笑鄧艾吃。豪鷹毛崱屴，猛馬氣佶僳。」

• 劉克莊：「十里稀逢寸地平，且無木影蔭入行。鳧飛難學王喬舄，魚貫全如鄧艾兵。」

• 楊巨源：「天低荒草誓師壇，鄧艾心知戰地寬。鼓角迥臨霜野曙，旌旗高對雪峰寒。」

• 魏靖：「儻使平反者數人，眾共詳覆來俊臣等所推大獄，庶鄧艾獲申於今日，孝婦不濫於昔時，恩渙一流，天下幸甚。」（《舊唐書·刑法志》）

• 李士謙：「鄧艾為牛。」（《北史·李士謙傳》）

• 洪咨夔：「蜀庸無與守，魏吃浪成名。血已洿砧機，魂猶饕酒牲。柏溪融雪瀉，玉案倚雲橫。瀦剃莫留跡，山川方氣平。」（《毀鄧艾廟》）

• 李新：「高鳥無餘弓自除，由來名盛不堪居。易揮道左降王縛，難弭朝端謗篋書。更欲平吳功未就，可憐出蜀智何疏。鳳台山月知冤魄，夜夜停光照故墟。」（《賦鄧士載祠》）

• 孟知祥：「奈何躁憤，自毀功庸，入此檻車，還為鄧艾，深可痛惜，誰肯愍之！」（《舊五代史·唐書·康延孝傳》）

• 何去非：「觀艾之為將也，急于智名而銳于勇功喜激前利而忘顧後患者也。艾常以是勝敵矣，而卒結禍于其身者，亦以此也。始鐘會以十萬之勁而趨劍閣。姜維以摧折之師，憊于奔命，雖能拒扼，而終非堅敵也。艾為主帥，不務以全策縻之，乃獨以其兵萬人，自陰平邪徑而趨江油，以襲劉禪。蓋出其不意，而行無人之境七百餘里，鑿山險，治橋閣，岩谷峻絕，士皆攀緣崖木，投墮而下。又糧運不繼，而艾至于以氈自裹，轉運而下。嗚乎！可謂危矣。士皆殊死決戰，僅獲破諸葛瞻之師，而劉禪悸迫，即時束手。使禪獨忍數日之不降，以待援師之集，則艾為以肉齒餓虎矣。艾一不濟，則鐘會十萬之師，可傳呼而潰矣。艾以其身為僥倖之舉者，乃求生救則之計，非所謂取亂侮亡之師，而亦非大將自任之至數也。是役也，非艾無以取勝于速，而其勝也有出于幸。使其不幸而至于潰敗者，亦艾致也。夫奇道之兵，將以掩覆于其外，必有以應聽于其內，然後可與勝期而功會也。」

• 陳亮：「又二百餘年，遂為三國交據之地，諸葛亮由此起輔先主，荊楚之士從之如雲，而漢氏賴以復存於蜀；周瑜、魯肅、呂蒙、陸遜、陸抗、鄧艾、羊祜皆以其地顯名。」（《宋史·陳亮傳》）

• 陳元靚：「赫赫皇魏，時生寶臣。忠衛社稷，志靜煙塵。蕩平巴蜀，恢廟咸秦。英銳不泯，激後之人。」

• 項忠：「昔馬援薏苡蒙謗，鄧艾檻車被徵。功不見錄，身更不保。」（《明史·項忠傳》）

• 陳普：「劉葛元非百世讎，緣崖攀木作猿猴。瞻崇艾會誰芳臭，死國沉身各二頭。」「滅吳不解誅宰嚭，拜假何須便不咨。受任兩無曹與馬，檻車破了欲何之。」

• 黃道周：「艾凡遇境，規度其宜。不知者笑，知者驚奇。魏蓄田谷，破吳用之。田無水利，將何以滋。艾請開導，妙論皆施。偕淮拒蜀，揣度姜維。當渡不渡，襲洮無疑。急往先備，方不受欺。計蜀五利，料難直馳。陰平斜徑，腹心所依。拼死涉險，捨命成危。裹氈死戰，方得濟師。其功異績，成于一時。惜居不善，身首皆夷。算人妙矣，苦不自知。」（《廣名將傳》）

• 羅貫中：「當年鄧艾襲西川，曾把陰平石徑穿。 越嶺雄兵齊貫索，臨岩大將自披氈。五丁破路應難及，三國論功合讓先。漢祚將終須換主，直饒山向上摩天！」「自幼能籌畫，多謀善用兵。凝眸知地理，仰面識天文。馬到山根斷，兵來石徑分。功成身被害，魂繞漢江雲。」

• 盧弼：「鄧艾耄年，裹氈履險，報國精忠，允宜彰表。」「艾隨時隨事，皆有經國遠猷，竟為鐘、衛所忌，慘死毒手，千秋而下，惜此美才。」（《三國志集解》）

藝術形象

動漫遊戲

• 《真三國無雙系列》（光榮公司開發，小原雅人配音）

• 《三國志姜維傳》

• 漫畫《火鳳燎原》（陳某）：於赤壁之戰篇登場，為張遼之手下，並隨張遼偽裝成荊州難民突襲駐守海昏的太史慈。

影視

• 中國中央電視台電視劇《三國演義》（1994年）：王洪光

• 中國電視劇《大軍師司馬懿之軍師聯盟》（2017年）：劉凌志