The discourse of popularizing legal knowledge is embodied in the legal practice of legislation，law enforcement，judicature，law-abiding，etc. It has an organic connection and a high degree of integration with the overall rule of law，which is interdependent，transformable and compound. Based on the general characteristics of China’s legal popularization practice and focusing on the actual effect of it，this paper tries to solve the problems relevant to discourse system in legal popularization practice. It analyzes the operation mechanism and value of the “people first” concept，the unique discourse system of “trinity”，and the “law enforcement and law popularization” responsibility system in China. It is proposed that China should always adhere to people-centered development in popularizing legal knowledge and implement the legal responsibility system to realize the legal transformation of legal knowledge，so as to effectively enhance the effectiveness of legal knowledge popularization.