Abstract:This paper selects 14 frequent factors that affect trust on the basis of literature retrieval, and extracts 8 common factors by principal component analysis. In this study, trust is divided into 3 categories characterized by trusted party, bilateral exchanges and the objective environment. The mechanism model, which is on influencing factors of inter organizational trust in PPP project, is established based on fuzzy cognitive map (FCM). The weights of each concept nodes are calculated by the combination of fuzzy semantics and COG method. This paper finds that there is a certain correlation between different influencing factors, and opportunism behavior will directly threat the trust between government and the private sector. Other factors are positively related to trust on different levels.