[Purpose/significance] Think tanks play an increasingly important role in national governance, and the study of knowledge innovation of think tanks is important in improving the service level of think tanks and enhancing the core competitiveness of think tanks in China. [Method/process] The article first defines the connotation of knowl⁃ edge innovation of think tanks, and summarizes the special characteristics of the innovation such as cost constraints, based on specific business and development stage of think tanks. Secondly, it analyzes the knowledge innovation level of think tanks, determines that the knowledge innovation of think tanks is divided into two levels: project innovation and organization innovation, and summarizes the subject, motivation, goal and characteristics of the two levels innova⁃ tion. Finally, a process model of knowledge innovation in think tanks is proposed based on the two innovation levels. [Result/conclusion] The realization of knowledge innovation requires certain conditions, and think tanks need to pro⁃ vide corresponding safeguards in terms of organizational resources, organizational systems, organizational structures, management styles, and organizational cultures, so as to promote continuous knowledge innovation, increase knowledge assets, and improve the competitiveness of think tanks.