Gong Zizhen abandoned the tradition that the public interest is prior to personal interest, and proposed “the private” theory. He believed that everyone has “selfishness”, and he criticized the traditional view of “the Public and the Private” respectively from the field of epistemology and ethics. His theory has positive influence on fighting back traditional Orthodoxy and gives prominence to the individual value and will, which endows the “Public-Private Distinction” a strong flavor of the times and modern human color. It is significant to understand the “ancient and modern”, “Chinese and Western” debate and save the current political situation and national destiny. However, due to a variety of factors, Gong Zizhen’s “the private” theory did not clarify what is “private” on earth, and also did not address the causes of “private” or the relativity between “public”and “private”. This makes Gong Zizhen’s “the private” theory less precise, and exerts negative effects to the development of the “public”and“private”realationship for future generations.