Later, he served as a military officer in the state of Cao Wei during the Three Kingdoms period.
Sometime in the 190s, Yin Li, along with Zang Ba, Sun Guan (孫觀), Wu Dun (吳敦), Chang Xi (昌狶) and others, formed a small army, with Zang Ba as their chief, and garrisoned at Kaiyang County (開陽縣; present-day Linyi, Shandong).
After Lü Bu's defeat and death at the Battle of Xiapi later that year, Zang Ba and his followers willingly surrendered to Cao Cao and became his subordinates.
Yin Li served as the Administrator of Dongguan Commandery (東莞郡; around present-day Yishui County, Shandong).
[6] Between October 222 and January 223,[6] Yin Li fought in the Battle of Dongkou against Wei's rival state, Eastern Wu.