Infrastructure construction directly affects the urban economic growth and social progress. At present，the demand of urban infrastructure construction is huge；At the same time demand diversity and standards are also improved. The government as a single investor，investment budget pressure and risk are increasing. Evidences show that PPP（Public Private Partnership）mode helped the construction of infrastructure，while government，society and the non-public sector can be realized to win more. In this paper，combined with the status quo of the PPP mode in infrastructure construction，Analyzes the current restriction for the application of PPP mode in infrastructure construction mechanism，factors other than three aspects such as the non-public sector and the government，discusses on the causes of the problem，And puts forward the establishing reasonable control system，strengthen the policy recommendations such as training and strengthen the spirit of the agreement.