This study analyzed 5 cases of the private enterprise to participate in PPP projects and extracted 11 major influencing factors for it as follows: returns on investment(ROI), operational efficiency, policies and regulations, lack of government commitment, fair competition, risk distribution, governmententerprise relationship, government concept, risk bearing capacity, entrepreneur opportunity identification and technical management experienceBased on ISM (interpretation of structural model method), A multilevel hierarchical structure model(EGM)of influencing factors for private enterprises to participate in PPP projects is constructedWe have concluded the three factors that influence the participation of private enterprises: marketled factors, governmentled factors and enterpriseled factorsIn addition, this study puts forward several suggestions from the government and the enterprise level to improve the participation of private enterprises