The Battle of Pengcheng was fought in Pengcheng (present-day Xuzhou, Jiangsu, China) in 205 BC between the kingdoms of Western Chu and Han, led by Xiang Yu and Liu Bang respectively. The Han forces were unprepared and suffered heavy losses. Several of Liu Bang's family members were captured and some of his allies defected to Chu as a result of his defeat.

In the spring of 205 BC, Xiang Yu was putting down rebellions in the Qi kingdom, following all the way to the northern coast of the Shandong peninsula a campaign of terror: burning homes; burying alive prisoners-of-war; capturing women, the weak, and the elderly.Tian Heng, brother of Tian Rong, the slain former ruler of Qi, gathered tens of thousands of soldiers and rebelled in Chengyang (in present-day Qingdao, Shandong). At the beginning of summer, Tian Heng installed Tian Rong's son Tian Guang as King of Qi. Xiang Yu was unable to dislodge him, but planned on dealing with Qi first before returning his military attention to Han.

With Xiang Yu thus occupied, Liu Bang collected a force of 560,000 troops from his subordinate lands, and marched east to attack Chu. En route, he encountered Peng Yue, who joined his cause upon promise of a fiefdom in Wei. As opposed to combining forces, Liu Bang sent Peng Yue's 30,000 troops to pacify the surrounding area. Liu Bang's army entered Xiang Yu's capital of Pengcheng (present-day Xuzhou, Jiangsu) apparently unopposed, looting its valuables and taking its women, but discipline was lax and each day found the Han troops deeper in their cups.

Hearing of the fall of Pengcheng, Xiang Yu ordered the bulk of his forces to maintain the attack on Qi, while he personally led 30,000 crack troops to retake the capital. He encamped about ten miles from the city, in present-day Xiao County, Anhui. At dawn, Xiang Yu launched an attack on Pengcheng, and by noon had broken the unprepared Han army.

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