The princedom of the empire is very important; if the princedom is not good, the empire will end. No matter how powerful Qin Emperor I was, and his successor is incompetent, the Great Qin Empire would be finished and cannot develop continuously. Liu Bang established the Han Empire. Liu Bang found that the prince Liu Ying was weak and lacked the ability to rule. He always wanted to displace the princedom of Liu Ying, but Empress Lu tried his best to protect the princedom of Liu Ying, and Liu Bang finally found it very difficult. After the development of the situation, Han Empire was almost captured by Lu family. This paper explains this phenomenon from the viewpoint of complexity theory.