Wei Bao was a member of the royal house of the state of Wei 魏 during the very late Warring States period 戰國 (5th cent.-221 BCE). When the first rebellions against the Qin dynasty broke out Wei Bao, together with his brother Wei Jiu 魏咎, joined the rebel leader Chen Sheng 陳勝. The latter made Wei Jiu king of Wei but his army was soon crushed by the Qin general Zhang Han 章邯.
Wei Jiu died and Wei Bao fled to the south where he became a general of King Huai of Chu 楚懷王. He was able to reconquer the territory of Wei and proclaimed himself king of Wei. He supported the rebel troops fighting against Zhang Han. After the successful battle of Julu 巨鹿 (modern Pingxiang 平鄉, Hebei), he followed the hegemonial king Xiang Yu to occupy the metropolitan area.
In 206 Xiang Yu made him king of Western Wei 西魏, with the residence at Pingyang 平陽 (modern Linfen 臨汾, Shanxi). When the war between Liu Bang 劉邦, the eventual founder of the Han dynasty 漢 (206 BCE-220 CE), and Xiang Yu broke out, Wei Bao surrendered to Liu Bang. After the latter's defeat at Pengcheng 彭城, he first accompanied Liu Bang to Xingyang 滎陽 and then asked to be allowed to return to Wei.
Back home, he declared his alliance with Liu Bang invalid. Liu Bang therefore sent general Han Xin 韓信 to punish him. Wei Bao was captured but Liu Bang pardoned him and appointed him governor (taishou 太守) of the commandery of Yingyang. When this city was invaded by Xiang Yu, Liu Bang's advisors doubted the loyaly of Wei Bao, and he was killed by general Zhou Ke 周苛.