Early life and service under Yang Feng

Xu Huang was born in Yang County (楊縣), Hedong Commandery, which is located southeast of present-day Hongtong County, Shanxi, in the late Eastern Han dynasty. He served as a minor official in the commandery office in his youth. Later, he became a subordinate of Yang Feng, a former White Wave Bandit who later became a general under the Han central government. Xu Huang later followed Yang Feng to attack rebels and was commissioned as a Cavalry Commandant (騎都尉) as a reward for his efforts.

Between 192 and 195, Li Jue and Guo Si controlled the Han central government and held the figurehead Emperor Xian hostage in the imperial capital, Chang'an (present-day Xi'an, Shaanxi). In 195, internal conflict broke out between Li Jue and Guo Si, whose respective factions started warring with each other in the streets of Chang'an. Yang Feng and Xu Huang were Li Jue's subordinates at the time. In the same year, Xu Huang managed to convince Yang Feng to escort Emperor Xian from Chang'an back to the old Han imperial capital, Luoyang. After Emperor Xian made it safely to Anyi County (安邑縣; west of present-day Xia County, Shanxi), he rewarded Xu Huang by granting him the peerage of a Marquis of a Chief Village (都亭侯).

After they returned to Luoyang with Emperor Xian, internal conflict broke out between the generals Han Xian and Dong Cheng, who were among those who escorted the emperor back to Luoyang. During this time, Xu Huang persuaded Yang Feng to summon the warlord Cao Cao to Luoyang to help them deal with the crisis and protect the emperor. In early 196, Cao Cao and his troops showed up in Luoyang and fetched Emperor Xian to their base in Xu (許; present-day Xuchang, Henan), which became the new Han imperial capital. Yang Feng initially wanted to heed Xu Huang's suggestion and join Cao Cao, but ultimately refused and went his own way. Xu Huang followed him.

In late 196, after Cao Cao defeated Yang Feng in battle at Liang State (梁國; around present-day Shangqiu, Henan), Xu Huang pledged allegiance to Cao Cao.

Cao Caos campaigns in central and northern China

Cao Cao sent Xu Huang with an army to attack rebels at Juan County (卷縣; west of present-day Yuanyang County, Henan) and Yuanwu County (原武縣; present-day Yuanyang County, Henan). Xu Huang defeated them and was promoted to Major-General (裨將軍).

During the battles between Cao Cao and Lü Bu in Xu Province in 198, Xu Huang attacked and defeated Lü Bu's subordinates Zhao Shu (趙庶) and Li Zou (李鄒). With aid from Shi Huan, he also defeated and killed Sui Gu (眭固) in Henei Commandery (河內郡; around present-day Jiaozuo, Henan).

In the year 200, during the Battle of Guandu between Cao Cao and Yuan Shao, Xu Huang participated in the early skirmishes at Boma (白馬; near Hua County, Henan) and Yan Ford (延津; present-day Yanjin County, Henan), where he defeated the warlord Liu Bei – who had joined Yuan Shao after losing Xu Province – and Yuan Shao's generals Yan Liang and Wen Chou. He was promoted to Lieutenant-General (偏將軍) for his achievements, and later joined Cao Hong in eliminating rebels led by Zhu Bi (祝臂) at Yinjiang (氵隱 疆; southwest of present-day Xuchang, Henan).

Yuan Shao had stored his supplies at a depot in Gushi (故市; southwest of present-day Yanjin County, Henan). Cao Cao sent Xu Huang and Shi Huan to attack this position. They defeated the defenders at Gushi and burnt down Yuan Shao's grain carts, forcing Yuan Shao to call for relief supplies in response to this raid. Xu Huang received the title of a Marquis of a Chief Village (都亭侯) for his contributions.

A few years later, Xu Huang joined Cao Cao on a campaign against the heirs of Yuan Shao, who had died in 202. In 203, Han Fan (韓範), the Prefect of Yiyang County (易陽縣; northeast of present-day Handan, Hebei), pretended to surrender to Cao Cao while buying time to strengthen his defences. Xu Huang then wrote a letter to Han Fan, tied it to an arrow and fired it into the county. Han Fan became convinced after reading Xu Huang's letter and decided to surrender Yiyang County without putting up resistance.

Before the fall of Yiyang County, Xu Huang went to see Cao Cao and asked him to refrain from massacring the population after Han Fan surrendered. The rationale of their final decision was entirely based on tactical consideration, which was to induce other enemy territories into voluntarily surrendering by setting an example. Cao Cao approved Xu Huang's suggestion.

Xu Huang later set up an ambush and routed the Yuans' forces at Maocheng (毛城), defeated Yuan Tan at the Battle of Nanpi, and suppressed a revolt in Pingyuan Commandery (平原郡; around present-day Dezhou, Shandong). He also participated in Cao Cao's campaign against Yuan Shang, Yuan Xi and the Wuhuan tribes which led to the Battle of White Wolf Mountain in 207. Xu Huang was further promoted to General Who Sweeps Across the Wilderness (橫野將軍) for his contributions in battle.

Battle of Jiangling

In 208, Xu Huang followed Cao Cao to pacify Jing Province (covering present-day Hubei and Hunan), and participated in the Battle of Red Cliffs in the winter of 208–209. When Cao Cao retreated north after his defeat at Red Cliffs, Xu Huang was ordered to stay behind with Cao Ren in Jiangling County to resist attacks by Sun Quan's forces.

During this time, Xu Huang was stationed at Fancheng (樊城; present-day Fancheng District, Xiangyang, Hubei) and he defeated opposing forces in Zhonglu (中廬), Linju (臨沮) and Yicheng (宜城) counties. During the Battle of Jiangling, he joined Man Chong in attacking Guan Yu at Han Ford (漢津), and Cao Ren in resisting attacks by Zhou Yu at Jiangling.

Cao Caos northwestern campaigns

In 210, Xu Huang led his troops to attack rebels in Taiyuan Commandery (太原郡; around present-day Taiyuan, Shanxi), besieged them in Daling County (大陵縣; northeast of present-day Wenshui County, Shanxi), and defeated and killed the rebel leader Shang Yao (商曜).

In 211, when Han Sui and Ma Chao led a coalition of northwestern warlords to start an uprising in Liang Province (covering parts of present-day Shaanxi and Gansu), Cao Cao ordered Xu Huang to move to Fenyin County (汾陰縣; southwest of present-day Wanrong County, Shanxi) and pacify the people in Hedong Commandery. He also awarded Xu Huang gifts of cattle and alcohol, and allowed him to repair and clean up his ancestors' tombs.

When Cao Cao led his forces to Tong Pass to engage the coalition, he became worried that he could not cross the Wei River to attack the enemy so he consulted Xu Huang for advice. Xu Huang suggested to Cao Cao to send him north and cross the Yellow River via Puban Ford to circumvent Tong Pass from the west of the river.

Cao Cao approved Xu Huang's plan and sent him and Zhu Ling to lead 4,000 troops across the river. They crossed Puban and started pitching camps, but before the defence fortification was completed, one of the coalition members, Liang Xing (梁興), discovered their presence and led some 5,000 troops to attack them. Xu Huang and Zhu Ling managed to hold off Liang Xing and allow Cao Cao and his remaining forces to cross the river.

After Cao Cao's victory at Tong Pass, he sent Xu Huang and Xiahou Yuan to pacify the various Di tribes in Yumi County (隃麋縣; east of present-day Qianyang County, Shaanxi) and Qian County (汧縣; south of present-day Long County, Shaanxi). Xu Huang and Xiahou Yuan later rendezvoused with Cao Cao's main army at Anding Commandery (安定郡; around present-day Zhenyuan County, Gansu). After Cao Cao had returned to Ye (in present-day Handan, Hebei), he sent Xu Huang and Xiahou Yuan again to suppress revolts in Fu County (鄜縣; southwest of present-day Huangling County, Shaanxi) and Xiayang County (夏陽縣; southwest of present-day Hancheng, Shaanxi), where they defeated Liang Xing and forced some 3,000 civilian households into submission.

When Cao Cao embarked on another campaign in western China to attack the warlord Zhang Lu in Hanzhong, he sent Xu Huang with a separate force to pacify the Di tribes living in Du (櫝) and Chouyi (仇夷) mountains. Xu Huang succeeded and was promoted to General Who Pacifies Bandits (平寇將軍). Later, Xu Huang also lifted rebels' siege on Zhang Shun (張順), one of Cao Cao's officers, and defeated the rebel leader Chen Fu (陳福) and destroyed some 30 rebel camps.

Hanzhong Campaign

Cao Cao returned to Ye (in present-day Handan, Hebei) after his victory over Zhang Lu at the Battle of Yangping in 215. He left Xu Huang and Xiahou Yuan behind to defend Hanzhong Commandery against attacks by Liu Bei.

During this time, Liu Bei sent Chen Shi to lead troops to cut off Xiahou Yuan's supply routes at Mamingge (馬鳴閣), Hanzhong's main communication line. Xu Huang led a separate detachment to launch a fierce attack on Chen Shi and defeated him. The casualty rate on Chen Shi's side was very high as many of his soldiers were forced to jump off the cliff during the attack.

Cao Cao was delighted when he heard of the victory and he gave orders to Xu Huang: "This pass is a crucial gateway into Hanzhong. Liu Bei intends to isolate the pass and then move on to conquer Hanzhong. You have done well in foiling the enemy's attempt." Cao Cao then personally led reinforcements to Hanzhong Commandery to counter Liu Bei's advances.

Battle of Fancheng

Xu Huang's most glorious moment in his military career came at the Battle of Fancheng in 219. When Fancheng (樊城; in present-day Xiangyang, Hubei) and Xiangyang were besieged by Liu Bei's general Guan Yu, Cao Cao first sent Yu Jin to lead a relief force to lift the siege but Yu Jin's seven armies were destroyed by a flood. Cao Cao then ordered Xu Huang to lead a second relief force to lift the siege. Cao Ren, the general defending Fancheng, and Lü Chang (呂常), who defended Xiangyang, were both under siege for months.

Knowing that most of his soldiers were composed of new recruits without training, Xu Huang did not go straight into battle but camped behind the enemy at Yanglingbei (陽陵陂; northwest of present-day Xiangyang, Hubei) to impose a deterrent effect. In the meantime, Cao Cao sent subordinates Xu Shang (徐商) and Lü Jian (呂建) to assist Xu Huang and instructed Xu Huang to advance only when Xu Shang, Lü Jian and all other reinforcements had arrived.

At the time, Guan Yu had set up a camp at Yancheng (偃城; north of present-day Xiangyang, Hubei). When Xu Huang showed up, he ordered his troops to pretend to dig trenches around Yancheng to fool the enemy into thinking that they were trying to cut off the supply routes leading to Yancheng. The enemy fell for his ruse, burnt down their camp and abandoned their position, thus allowing Xu Huang to gain a foothold at Yancheng. After capturing Yancheng, Xu Huang pressed on and set up two linked camps about 30 zhangs away from Guan Yu's encirclement. Before Xu Huang attacked, Cao Cao sent Yin Shu (殷署), Zhu Gai (朱蓋) and other officers to lead another 12 military units to support him.

Guan Yu's encirclement was made up of five camps – one main camp leading the siege and four supporting camps. Xu Huang deliberately spread news that he was going to attack the main camp to trick Guan Yu into strengthening his defences at the main camp. In the meantime, he secretly sent his forces to attack the four supporting camps and succeeded in destroying them. When Guan Yu saw that the four camps were down, he personally led 5,000 troops to engage the enemy. Xu Huang launched a fierce attack on Guan Yu and succeeded in defeating him and lifting the siege on Fancheng. During Xu Huang's attack, many of Guan Yu's soldiers panicked and fled towards the nearby Han River, where they drowned.

When Cao Cao heard of the victory, he praised Xu Huang: "The enemy formation was very thick, yet you managed to achieve victory and destroyed their camps and killed so many of their men. I have fought in battles for over 30 years, but I have never heard of any person in history who attempted to break a siege by launching a direct attack on the enemy's encirclement. The situation at Fancheng and Xiangyang was much worse than that at Ju and Jimo. Your achievements are comparable to those of Sun Wu and Rangju."

The Shu Ji (蜀記) recorded an incident about Xu Huang meeting Guan Yu on the battlefield. Xu Huang had a close personal friendship with Guan Yu. They often chatted about other things apart from military affairs. When they met again at Fancheng, Xu Huang gave an order to his men: "Whoever manages to take Guan Yunchang's head will be rewarded with 1,000 jin of gold." Guan Yu was shocked and he asked Xu Huang: "Brother, what are you talking about?" Xu Huang replied: "This is an affair of the State."

Upon Xu Huang's return, Cao Cao went seven li out of Xuchang to greet him, giving him full credit for securing Fancheng and Xiangyang. Throughout the field reception, the soldiers of other commanders shifted about in order to get a better view of Cao Cao, but Xu Huang's men stood stationary in neat files. Seeing this, Cao Cao remarked: "General Xu has truly inherited the style of Zhou Yafu."

Service under Cao Pi and Cao Rui

Following Cao Cao's death in March 220, his son Cao Pi succeeded him and inherited his vassal king title as the King of Wei (魏王). Xu Huang continued to be heavily trusted by Cao Pi, and he was appointed General of the Right (右將軍) and enfeoffed as the Marquis of Lu District (逯鄉侯).

In late 220, Cao Pi usurped the throne from Emperor Xian, ended the Eastern Han dynasty, and established the state of Cao Wei (or Wei) with himself as the new emperor. After his coronation, Cao Pi promoted Xu Huang from a district marquis to a county marquis under the title "Marquis of Yang" (楊侯).

Later, Cao Pi ordered Xu Huang and Xiahou Shang to lead an army to attack Shangyong Commandery (上庸郡; in present-day northwestern Hubei). After completing his mission, Xu Huang moved to the garrison at Yangping County (陽平縣; present-day Shen County, Shandong), so his marquis title was changed to "Marquis of Yangping" (陽平侯).

Cao Pi died in 226 and was succeeded by his son Cao Rui as the emperor of Wei. During that time, Xu Huang successfully repelled an invasion on Xiangyang by the Wu general Zhuge Jin. For his contributions, he was awarded another 200 taxable households in his marquisate, bringing the total number to 3,100.

When Xu Huang became seriously ill later, he gave instructions that he was to be given a simple burial after his death. He died in 227 and was granted the posthumous title "Marquis Zhuang" (壯侯), which literally means "robust marquis".

Xu Huang's son, Xu Gai (徐蓋), inherited his father's peerage as the Marquis of Yangping. After Xu Gai died, his son Xu Ba (徐霸) succeeded him as the next Marquis of Yangping. Cao Rui later divided their marquisate and awarded marquis titles to two descendants of Xu Huang.

Appraisal

Chen Shou concluded Xu Huang's biography in the Sanguozhi with a brief appraisal:

In Romance of the Three Kingdoms

Xu Huang is a character in the 14th-century historical novel Romance of the Three Kingdoms, which romanticises the events before and during the Three Kingdoms period of China. He makes his first appearance in Chapter 13 as a subordinate of Yang Feng. Xu Huang and Yang Feng escort Emperor Xian back to Luoyang after the emperor escapes from Li Jue and Guo Si's clutches in Chang'an.

When Cao Cao comes to Luoyang to fetch the emperor to his base in Xuchang, Yang Feng sends Xu Huang to stop him. Cao Cao knows on first sight that Xu Huang is an extraordinary man so he orders Xu Chu to duel with Xu Huang. Neither side can gain an advantage over each other after 50 bouts, and by then, Cao Cao is very impressed by Xu Huang's skill. Not wanting either of the two men to get hurt, Cao Cao calls for Xu Chu to retreat. Man Chong, one of Cao Cao's subordinates, knows that his lord wants to recruit Xu Huang so he volunteers to persuade Xu Huang to defect to their side. That very night, Man Chong disguises himself as a common soldier, sneaks into Xu Huang's tent and manages to convince him to switch allegiance to Cao Cao. Man Chong then suggests that Xu Huang slays Yang Feng to prove his loyalty to Cao Cao, but Xu Huang refuses to kill his former superior out of respect for him.

In the novel, Xu Huang meets his end during the Xincheng Rebellion when he is struck by an arrow in the forehead fired by the rebel leader Meng Da. His men immediately take him back to camp, where the physician removes the arrow and tries to heal him, but Xu Huang eventually dies later that night. The novel states that he is 59 years old at the time of his death. This figure, however, is not supported by any evidence from historical records.

In popular culture

Xu Huang is featured as a playable character in Koei's Dynasty Warriors and Warriors Orochi video game series. He also appears in all instalments of Koei's Romance of the Three Kingdoms strategy game series.

生平

護駕聖上

徐晃早年在郡裡作小吏，因隨車騎將軍楊奉討伐賊寇有功，被拜為騎都尉。

初平三年（192年），王允和呂布謀殺董卓，董卓部將李傕、郭汜等人攻破長安城，又殺王允等人。徐晃說服楊奉護送漢獻帝東入洛陽，楊奉接受這個建議。漢獻帝渡河至安邑時（今山西夏縣北），封賞保駕有功人員，徐晃被封為都亭侯。

遂陷賊圍

興平三年（196年）初， 漢獻帝在河內太守張楊、興義將軍楊奉等朝廷百官的保護之下，回到洛陽，楊奉被拜為車騎將軍，駐兵大梁。徐晃見大將軍兼司隸校尉韓暹和衛將軍董承之間爭鬥日益加劇，就勸楊奉歸附曹操，楊奉決定聽從徐晃的建議。秋，曹操保護著漢獻帝要從舊都洛陽遷都到許縣，並定都許昌改稱許都，改元建安。楊奉在韓暹的挑撥下又改變主意，跟韓暹一起出兵去劫駕，在梁地被曹軍殺得大敗，徐晃則投奔曹操。曹操分兵給徐晃，派其攻打卷、原武兩地，獲勝，被拜為裨將軍。隨曹操攻呂布，降呂布將領趙庶、李鄒等人，後來又與史渙在河內斬殺眭固，立下大功。

拜將封侯

建安五年（200年），徐晃隨曹操擊敗徐州的劉備，又隨曹操擊敗顏良，攻克白馬，進至延津，在此擊殺文醜，被拜為偏將軍。徐晃與曹洪攻打祝臂獲勝，謀主荀攸對曹操說：「袁紹的糧車旦夕間就到，其押運糧草的將領韓猛，雖然勇猛但輕敵，出擊可以將他打敗」。曹操問：「誰可以擔當這個重任？」荀攸說：「徐晃可以。」曹操又派徐晃和史渙帶著幾千騎兵共同攻打韓猛，在故市截燒其輜重。此戰徐晃功勞最大，被封為都亭侯（一說亭侯）。

沉勇特立

建安九年（204年），曹操圍攻鄴城，又攻破邯鄲。易陽令韓范詐降而自守，曹操派徐晃前去攻打，徐晃兵臨城下，給韓范寫信，用箭射入城中，陳明利害，勸韓范投降。韓范被說服後改變主張，決定以全城投降。徐晃勸告曹操說：「如今袁譚、袁尚還沒有被擊敗，沒有攻下的城池都等待消息，如果今日滅易陽，明日那些城池都會死命防守，河北就沒有平定的那一天了。請求您招降易陽來給各城看，那樣他們都會望風歸順。」曹操採納他的意見，于是很快地翦除鄴城羽翼，攻克鄴城，奪得冀州。隨後徐晃又攻毛城，設伏兵大敗袁軍，攻破三屯。之後，徐晃又隨曹操征討袁譚以及平原叛賊，均大獲全勝。

建安十二年（207年），徐晃隨曹操及曹純北征烏桓，在白狼山之戰中，聽受張遼的調度大敗蹋頓，曹純督領虎豹騎俘獲蹋頓，蹋頓當陣為張遼斬殺。曹操最終討平烏桓，徹底剷除袁氏殘餘勢力，戰役結束後二十多萬民眾和烏桓部卒投降曹操。徐晃因從征有功，而被拜為橫野將軍。

建安十三年（208年），徐晃隨曹操南征，別屯樊城，攻中廬、臨沮、宜城，又與滿寵在漢津征討關羽。後曹操在赤壁之戰中為孫劉聯軍所敗，曹操留徐晃與曹仁共守南郡，抵抗吳將統帥周瑜的進攻。

建安十五年（210年），徐晃隨夏侯淵去太原平叛，攻克大陵，斬其首領商曜。

千軍突進

建安十六年（211年）， 以西涼割據勢力馬超、韓遂為首的聯軍，聚集十餘萬人馬，據守潼關抵抗曹操。曹操發兵進取關中，曹操命徐晃屯守汾陰，以鎮撫河東。曹操率軍到達潼關後，擔心無法順利渡過黃河，于是向徐晃問計。徐晃說：「您已經帶大兵到此，而敵人不再分兵守衛蒲阪，可知他們缺乏謀略。請給我一支精兵，渡過蒲阪津，作為大軍的先導，截斷敵人的後路，就可抓住他們了。」曹操同意此舉，派徐晃率四千精兵從蒲阪津（今山西永濟、陝西大荔朝邑之間黃河渡口）乘虛渡過黃河，陣地尚未建成，敵將梁興夜間率步騎五千餘人攻徐晃，徐晃將其擊走，隨即建立橋頭陣地，曹軍從此渡河，曹操又採納謀士賈詡的計謀「偽書疑心」，成功離間分化馬超和韓遂，斬成宜、李堪等將，最終大破關中軍。

敵戰當鏖

建安二十年（215年）， 曹操派徐晃與夏侯淵平定隃麋、汧諸氐，和曹操會師于安定。曹操還鄴後，又派徐晃與夏侯淵平鄜、夏陽餘賊，斬殺梁興，降三千餘戶。同年七月，徐晃隨曹操征討張魯，派徐晃討伐櫝、仇夷和山氐，皆歸降。因功升為平寇將軍。此戰中，徐晃解將軍張順之圍，擊賊陳福等三十餘屯，皆破之。同月，曹操回到鄴城，任命夏侯淵為都護將軍，督徐晃、張郃駐守陽平關。

建安二十三年（218年）， 劉備進攻漢中。同年四月，劉軍進至陽平關，夏侯淵、張郃、徐晃等率軍阻擊。劉備派部將陳式等十餘營襲擊馬鳴閣（今四川廣元北），企圖切斷曹軍後方通道，被徐晃擊敗，蜀軍自投山谷，死者甚多。曹操聽說後，非常高興，給了徐晃指揮軍隊的符節，並且下令說：「這一條閣道是漢中的咽喉險要之地。劉備欲斷絕西南與內地的聯繫，以取漢中，將軍一舉打亂劉備計畫，真是太好。」219年，夏侯淵於定軍山陣亡，曹操親自到漢中，撤出剩餘部隊。

定策群詳

建安二十四年（219年），曹操派徐晃協助曹仁征討關羽，駐于宛縣。正趕上漢水暴漲，于禁等全軍覆沒。關羽圍曹仁於樊城，又在襄陽包圍呂常等幾支部隊。當時徐晃所部多為新兵，難以與關羽爭鋒，於是進至陽陵坡駐紮。曹操又派將軍徐商、呂建到徐晃那裡，傳令：「要等到兵馬集結後，一起前進。」當時關羽前部屯偃城，徐晃能打裝作不打作防禦，並切斷關羽軍後路。關羽軍懼被圍，燒營撤走，徐晃佔據偃城，兩面連營，漸向圍城關羽軍逼近，徐晃軍營距關羽所圍僅三丈。曹操又先後派殷署、朱蓋等十二營兵進至偃城，悉歸徐晃指揮。關羽軍主力屯圍頭，另屯有四塚。

徐晃以聲東擊西戰術，揚言欲攻圍頭，卻出其不意突襲四塚。關羽恐四塚有失，自率步騎五千出戰，被徐晃擊敗。徐晃趁勝追擊，沖入關羽軍圍內，關羽軍大敗，很多自投沔水而死。關羽遂撤圍退走，樊城圍解。曹操下令說：「用鹿角十重把敵人圍繞塹，將軍致戰全勝，遂陷賊圍，多斬首虜。我用兵三十餘年，及所聞古時善於用兵的人，還沒有能夠長驅直入敵人的包圍。況且樊、襄陽之圍，勝過以前的莒、即墨之圍，所以將軍之功，勝過孫武、穰苴。」徐晃凱旋至摩陂，曹操親自出營七里迎接徐晃，並設宴慶賀，慰勞徐晃。曹操舉杯對徐晃說：「保全樊、襄陽，都是將軍你的功勞。」徐晃治軍嚴謹，令行禁止，當時諸軍雲集於摩陂，曹操案行諸營，不少士兵出陣圍觀，唯有徐晃部下軍營整齊，將士駐陣不動。曹操嘆道：「徐將軍可謂有周亞夫之風啊！」

殊立鴻勛

建安二十五（220年），曹操去世，曹丕即魏王位，封徐晃為右將軍，進封逯鄉侯。同年，曹丕稱帝，改元黃初，黃初元年，又進封徐晃為楊侯，與征南將軍夏侯尚在上庸攻打劉備軍守將劉封，攻破其軍。因徐晃鎮守陽平關，故改封為陽平侯。當初關羽北伐時，曹仁自樊城潰圍而出，孫權即派部將陳邵占領襄陽，曹丕命曹仁、徐晃打敗陳邵，奪回襄陽。

黃初三年（222年）九月，曹丕御駕親征東吳。魏文帝命征東大將軍曹休、前將軍張遼、鎮東將軍臧霸出洞口，大將軍曹仁出濡須，上軍大將軍曹真、征南大將軍夏侯尚、左將軍張郃、右將軍徐晃圍攻江陵。東吳料想曹魏不會善罷幹休，也做好防守軍事準備，讓建威將軍呂範督五軍率領建武將軍徐盛、揚威將軍孫韶、偏將軍全琮，以舟軍拒曹休，爆發洞口之戰，另一方面征北將軍朱然率領左將軍諸葛瑾、平北將軍潘璋、將軍楊粲防守江陵，爆發江陵防衛戰，裨將軍朱桓以濡須督身分統領偏將軍駱統、騎都尉周邵防守濡須抗拒曹仁，展開濡須口攻防戰。但是，徐晃與夏侯尚等人最終未能攻克朱然駐守的江陵，只好放棄攻勢而退軍。

黃初七年（226年）五月，魏文帝曹丕駕崩，魏明帝曹叡繼位。吳國乘機派左將軍諸葛瑾等攻襄陽，徐晃駐守襄陽抵禦，因為戰功增食邑200戶，前後共計3100戶。後來，徐晃得病，魏明帝親自派人為他尋找藥方。太和元年（227年），徐晃去世，諡曰壯侯，兒子徐蓋繼嗣。

其他

徐晃可能因為楊奉的關係，從歸順曹操直到去世，終生「不廣交援」，凡事都「儉約畏慎」，但與同郡關羽結為知己。據《三國志·關羽傳》裴注引《蜀記》記載徐晃的年紀應比關羽還大。

評價

• 曹操：「賊圍塹鹿角十重，將軍致戰全勝，遂陷賊圍，多斬首虜。吾用兵三十餘年，及所聞古之善用兵者，未有長驅徑入敵圍者也。且樊、襄陽之在圍，過於莒、即墨，將軍之功，逾孫武、穰苴。」、「徐將軍可謂有周亞夫之風矣。」（《三國志·徐晃傳》）

• 陳壽：「太祖建茲武功，而時之良將，五子為先。」、「性儉約畏慎，將軍常遠斥候，先為不可勝，然後戰，追奔爭利，士不暇食。」（《三國志》）

• 魚豢：「徐晃性嚴，驅使將士不得閒息。於時軍中為之語曰：『不得餉，屬徐晃。』晃聞此語，笑曰：『我槌破汝鎢錥耶？』」（《太平御覽·卷757 ◎器物部二○鎢錥》引《魏略》 ）

• 溫庭筠：「石苞羈賤，早遇何曾；魏武尊高，猥知徐晃。其後咸成啞，訖立鴻勛。簡冊增輝，尊彞動彩。」

• 韓儀：「徐晃沉詳，幼而特立。既克紹於門風，爰委用於舊土。未行真命，且假劇權。士心咸感於惠和，封部果臻於寧肅。」

• 范攄：「夫徐晃持刑，而行陣齊整；慕容貸法，而兵士傾心。寬猛相濟，故無不均。」

• 洪邁：「張遼走孫權于合肥，郭淮拒蜀軍于陽平，徐晃卻關羽于樊，皆以少制眾，分方面憂。」（《容齋隨筆》）

• 葉適：「以理勢而言，非徑入敵圍，固不能解圍全城。非于圍上破走救者，固不能得城全勝。然古今自非，見救至逆遁，則皆畏敵不敢救，少有如關羽及晃之真以勇力相遇而決勝者。客主單複之殊，陸抗能知之。此羽之所以終屈，而觀者之所當思也。」

• 郝經：「張遼、徐晃諸將壯猛有謀，亦關張之亞匹；然失身于操，終為勇而無義。」

• 羅貫中：「降明權成厚，爭津定策高。 揚名攻不備，陷敵戰當鏖。欲虜平襄漢，還屯振節旄。功逾孫子右，魏武過情褒。」

• 黃道周：「徐晃為將，處事精當。飛矢城中，既降不妄。受降招降，信義是望。超、遂反時，蒲城一障。守即不知，攻則有狀。渡而擊之，一時掃蕩。羽屯圍頭，四塚依杖。晃破四塚，圍頭引向。為將若茲，方據其上。」

• 王歆：「救樊之役，長驅入圍，中原平靖，徐晃之能可蓋霄壤。晃所部新軍，而能一戰成功，羽非上智，可知之矣。史載晃從楊奉時，已封都亭候，及後破袁紹運車，複封都亭侯，是晃前屬太祖，非歸也，或被禽而降者也。尾章首句無主語，不合乎文法，必有缺漏。」

• 何焯：「徐晃之解樊圍，一時奇功。」

• 毛宗崗：「徐晃聲東擊西，此沒彼現，只一員正將，兩員副將，寫來似有千軍萬馬之勢，可謂用兵之能者矣。晃之戰沔水，與張遼之戰合淝，仿佛相類。兩人皆有大將才，故關公與之友善。」

• 《辭海》：「長驅直入徐公明，一箭雙雕長孫晟。」

藝術形象

三國演義

在演義中，形象為手持長柄大斧武器的將領。初登場時，身分為楊奉部將。當楊奉與郭汜大戰之時，一馬當先斬了郭汜部將崔勇。日後楊奉與曹操交戰，曹操欣賞徐晃武藝，派遣滿寵擔任說客，秘密潛伏至徐晃帳中，一番遊說後，成功將徐晃納入其麾下。

加入曹操軍後，倍受曹操信賴，也與曾短暫投降曹營的關羽關係良好。在官渡、赤壁、馬超討伐戰等場合表現十分活躍。然而在漢水一戰，徐晃堅持己見佈下背水陣，與當時擔任副將的王平意見相左，最後被劉備擊敗，王平反叛，曹操最後也失去漢中。

劉備就任漢中王後，關羽發起荊州攻防戰，守將曹仁被圍困城中，曹操派遣徐晃為援軍前往救援，解除曹仁的危機。最後登場一幕，乃諸葛亮發動第一次北伐時，身處魏國上庸的孟達意圖回歸蜀國，徐晃以司馬懿的副將身分，跟隨征討孟達；在城前叫陣時，被孟達一箭射中額頭，回營後不治身死。

影視

• 香港電視劇《洛神》（1975年）：由周潤發飾演徐晃。

• 電影《關公》（1992年）：由楊光華飾演徐晃。

• 中國中央電視台電視劇《三國演義》（1994年）：由霍爾查、劉洪林、謝東、尼格木圖、崔向榮飾演徐晃，日語聲優為星野充昭。

• 台灣華視電視劇《三國英雄傳之關公》（1996年）：由管謹宗飾演徐晃。

• 中國電視劇《洛神》（2002年）：由華忠男飾演徐晃。

• 中國電視劇《武聖關公》（2004年）：由朱曉春飾演徐晃。

• 中國電視劇《三國》（2010年）：由陳威飾演徐晃。

• 中國電視劇《武神趙子龍》（2015年）：由馬永康飾演徐晃。

• 中國電視劇《大軍師司馬懿之軍師聯盟》（2017年）：由衛羽飾演徐晃。

動漫遊戲

• 真三國無雙系列、無雙OROCHI系列（光榮公司開發，山本圭一郎配音）

• 吞食天地II 赤壁之戰（卡普空開發）

• 三國演義 (動畫)

• 蒼天航路（王欣太）

• 火鳳燎原（陳某）