Chen Yu 陳餘 (d. 204 BCE) was a rebel against the Qin dynasty 秦 (221-206 BCE).
He hailed from Daliang 大梁 (modern Kaifeng 開封, Henan). Chen Yu was a very literate person and married the daughter of a rich merchant enabling him to travel a lot and establish connections. He had a deep friendship with Zhang Er 張耳, with whom he later rose against the Qin.
When the armies of Qin conquered his home state of Wei 魏, he had to hide himself because a prize was offered for his head. When Chen Sheng 陳勝 rose in rebellion against the Qin dynasty, Chen Yu joined and offered his help for the reestablishing of the old, pre-imperial order, urging Chen Sheng not to adopt the title of king but instead trying to conquer the hearland of the Qin empire. Chen Sheng did not appreciate him, and so he asked at least to be allowed to be entrusted with the conquest of the region of Zhao 趙.
He was able to conquer the capital of Zhao, Handan 邯鄲, and urged Wu Chen 武臣, one of the rebels, to proclaim himself king of Zhao. As General-in-chief (da jiangjun 大將軍) of Zhao, he was strong enough to ignorate Chen Sheng, the leader of the rebellion from then on. Chen Yu also invaded the territory of Yan 燕 more the north.
Not long after, Wu Chen was killed by Li Liang 李良. Chen Yu thereupon proclaimed himself King of Zhao. When the Qin general Zhang Han 章邯 besieged the city of Julu 巨鹿 (modern Pingxiang 平鄉, Hebei), Chen Yu asked for support, but Zhang Er refused, rating his former friend a coward. When the battle was over, Chen Yu became a commoner. Xiang Yu, the hegemonial king dominating China just after the downfall of the Qin dynasty, gave the kingdom of Zhao, now called Changshan 常山, to Zhang Er.
Enraged, Chen Yu asked Tian Rong 田榮, king of Qi 齊, for support, and attacked Zhang Er, drove him away and made Zhao Xie 趙歇 king of Zhao, while Chen Yu himself adopted the title of King of Dai 代.