The event tree analysis method and fuzzy set theory are used to analyze and evaluate the risk of enterprise merger and acquisition(M&A) from the perspective of industrial chain synergy. The main risk factors in each stage of m & a activities are analyzed, and the risk event tree analysis model of industry chain collaborative M&A is constructed according to the risk event sequence in M&A process. Then the probability evaluation algorithm of event occurrence is discussed based on fuzzy set theory and the process of risk value calculation is demonstrated according to the probability of event occurrence and the its loss rate. It solves the problem that it is difficult to quantify the risk evaluation value in the event tree method. Furthermore, it explores the key risk points of the industry chain collaborative M&A by the case study. It surly proves the feasibility and effectiveness of the method. Finally, management suggestions on risk control of industrial chain collaborative M&A are put forward according to the research results.