This thesis deals with some contemporary disputes of Gu Xiancheng‘s theory, and tries to reconstruct his statements using the Four Square Framework in order to respond to these disputes. To achieve the purpose, I will explain Gu Xiancheng's statements of practical theory and the backgrounds of these opinions first, and discuss why there are disputes between contemporary scholars’ theory. Then I will clarify whether these disputes exist or not. Second, I will explain Gu Xiancheng's theories on ontology, and analyze Gu Xiancheng’s standpoint about the famous argument “Neither Good Nor Evil.” At last, I will criticize the contemporary methodology for Gu Xiancheng theory. And I will explain what Gu Xiancheng’s thoughts should be through this criticism.