Analyzing the main factors of interconnection of telecom industry is the aim of this paper. A model is built to calculate the benefit from interconnection distributing in different telecom firms , and analyzed the incentive mechanism through game theory. It is concluded that the scale ratio between competitor and monopoly , policy of ac2 cess cost , discount rate and punish of refusing interconnection are the main factors affecting interconnection , and adjusting these factors may get both-win interconnection. According to real condition in China , the paper give the policy advice