At present，the lack of PPP legislation has become an important factor restricting the standardized and orderly development of PPP. This paper firstly makes a legal analysis on the current PPP policy environment，situation of PPP system and development tendency. The law on PPP should first adhere to the general principle of good faith，equal consultation，fairness and openness. About the essence of legal relation regulated by the law on PPP，this paper advocates “Dichotomy” to solve disputes. While opening the door for social capital to participate in PPP projects，we should pay attention to improving its exit mechanism，so as to solve the “worries” of social capital.