Modern think tank is one of the key symbols of modernization of national governance system and governance capacity. At the beginning of the 20th century, modern think tank came into being in Britain and America due to the increasing complexity of social, economic and national governance, and the empirical decision-making mode was insufficient. After more than a century, modern think tank has not only become a mature industry based on advanced knowledge, but also completed the institutionalized construction of the knowledge system of relevant think tank, which has become an important research field of mainstream social science, formed a stable research community, and bred a number of high-level research results. Think tank knowledge system and think tank practice formed a benign interaction. However, as the independent consciousness of think tank construction in China has just awakened and the practice of think tank has just started, all parties lack a clear understanding of the importance, significance and path of the institutionalized construction of think tank knowledge system, and the institutionalized construction of think tank knowledge system is still in the spontaneous stage. This paper argues that from the perspective of discourse system, discipline system and academic system, it is necessary to promote the institutionalization of the think tank knowledge system in China, so that the think tank knowledge system can be embedded into the mainstream social science, and realize the early evolution of the think tank knowledge system from the previous scientific stage to the conventional scientific stage.