The application and development of the PPP model has played a key role in promoting the development of the environmental protection industry. However，in the development process，the application forms of the PPP model vary according to the characteristics of the various environmental protection subdivisions. This report takes the development history of municipal environmental protection PPP as the starting point，and introduces the current development of PPP model in various sub-sectors of environmental protection industry，as well as the problems and risks it faces，to provide a better understanding and use of PPP in environmental protection.