Abstract: Competitive alliance is an emerging strategic mode. It has become a focus in alliance theoretical field because it is beneficial to the partners who reap competitive advantages by reaching synergistic effects. Based on data collected from 205 competitive alliances, the relationships between cooperative effects and their influencing factors are discussed and tested, especially the indirect impacts, from the angle of inside alliance by applying the regression analysis. The results demonstratethat both the structure of alliance and the internal risk are significant mediator variables. This means that the impacts of influencing factors on cooperative effects are partially or completely deliveredby those mediators, but not directly.