Abstract: The basic value, effect and influence factors of knowledge sharing are analyzed, revenue function of enterprise alliance is constructed, evolutionary game model of the cooperation of all parties is established, and the evolutionary stable strategy of the knowledge sharing group is researched. In this paper, the existence and stability of equilibrium in knowledge sharing group system are discussed under various coopetition situations, and the factors that affect the evolution equilibrium such as knowledge absorption ability, value-added, leveragability, synergy, negative reverse-impact, sharing cost, loss of reputation and marginal revenue are analyzed. The results show that probability of enterprise alliance forming a knowledge sharing stable state is in negative correlation with value-added, negative reverse-impact and sharing cost, and is in positive correlation with leveragability, synergy, and loss of reputation, while not related to knowledge absorption ability. It can promote the alliance to the ideal state by reducing the value of own kowledge, reducing the negative effect of knowledge sharing, establishing reputation mechanism and reducing the cost of knowledge sharing.