Abstract: Abstract：There is opportunism in retailers′ joint promotion, which results in the waste of manufacturers′ resources. In this paper, evolutionary game model is used to analyze the evolutionary path in the interactive process of joint promotion between manufacturer and retailer, and the influence of retailer opportunism on the evolutionary path is simulated.The results show that: retailers′ opportunism degree influences participants′ strategy choice in the joint promotion game, and the evolution path of the game is different under different opportunism degrees;the reason for the existence of opportunism is that the retailer obtains additional income through expense withholding, and whether the manufacturer governs opportunism depends on the relationship between the penalty income and the cost of governance and the degree of the retailers′ opportunism:if the opportunism is too large or too small, the manufacturer will choose the strategy of non governance; when retailers′ opportunism is greater than a certain value, the retailer will choose the strategy of non interception; when the opportunism is within a certain threshold, the market will be in a governance dilemma or the manufacturer′s “inaction” state according to whether the penalty income of the manufacturer is greater than the governance cost.

Key words: Key words：joint promotion, opportunism, evolutionary game