Political ethics, ruling ethics and administrative ethics as a result of the growing divergence in the practical field of politics are three connected links in practice, in theory, presents the logical evolution of hierarchy system, and on the core values are pointing in the public interest. Public interest should be understood as a dynamic historical process. Its main connotation developed from the order to the economic interests, and then to the overall and free development of man, which regulate the current practical and academic direction of political ethics, ruling ethics and administrative ethics. Especially for the current China's case, more in dual deconstruction and reconstruction, public interest should be unceasingly into reality, which everyone should be free and comprehensive developing.