Abstract: As the proportion of knowledge-intensive projects increased, knowledge collaboration has become the most important part of the organizational strategy of service outsourcings. In this paper, how the service outsourcing organiztion's productivity depends on the firm's knowledge collaboration is studied, importance of the bidirectionality, relationality and complementarity of shared knowledge in service outsourcing activities is asserted.Then,all of them are summarized into a conceptual model. From this point of view, a two stage dynamic game model is set up, and the game equilibrium between outsourcer and outsourcing is analyzed according to their two kinds of cooperation mode. Three propositions are proposed: Firstly, there are bidirectional incentives in knowledge sharing between outsourcer and outsourcing; Secondly, cooperative knowledge sharing decision model, which is based on the good relationship between enterprises, is beneficial for the organization; Finally, higher knowledge complementarity has a positive role in promoting knowledge sharing.

Key words: service outsourcing, knowledge collaboration, knowledge sharing, knowledge complementarity