We can know that the failure of ISD project may result from knowledge resource risk, including insufficient knowledge and failed to integrated available diversified knowledge. As a result, it is very important issue for ISD team that how to integration a large number of knowledge from diversified background team members. This study explores the affecting factors of knowledge integration within ISD team from team composition view and based on similarity-attraction theory. The theory framework starts form three dimensions, including demographic similarity, cognitive similarity and goal similarity, affecting the interpersonal attraction and then explores the impact of similarity of team members on team integration which includes social integration and knowledge. An empirical survey methodology is applied to test the research model and six hypotheses are developed in this study, and then we use PLS to analyze it. Our empirical results showed that goal similarity is significant affecting on interpersonal attraction. The study results also found that interpersonal attraction is a mediator between similarity and construct of team integration. In addition, social integration is an important antecedent of knowledge integration and similarity of team members also affect knowledge integration indirectly. In sum, unlike much prior research that focused on diversity-conflict view of team composition, we take similarity-attraction view and proposed a more comprehensive model to explore the affecting factors of knowledge integration. And this study provides some suggestions for the knowledge integration research.