Cao Song, Cao Cao's father, was killed by the Ministry of Tao Qian on his way to Yanzhou, which provided an excuse for Cao Cao to attack Xuzhou. But the real purpose of Cao Cao's attack on Xuzhou was because the military strength of Xuzhou grazing Tao Qian was weak at that time, but it occupied such a rich place in Xuzhou, and Cao Cao was jealous. Secondly, Yuan Shu and Yuan Shao were fighting with each other at that time. Cao Cao supported Yuan Shao, while Tao Qian supported Yuan Shu, which was also a reason for their different political positions.