Abstract: The co-specialization of platforms and complementors plays an important role in the construction of the innovation ecosystem. However, platform enterprises and complementors may have conflicting or complementary institutional logic respectively. If they want to achieve the goal of collaborative innovation, they will inevitably form a dominant institutional logic in the process of reaching a collaborative consensus, and then regulate the innovation activities and behaviors of both parties. But how does this dominant institutional logic emerge? What are their mechanisms? Past studies have rarely referred to such issues. Through the case study of OPPO, the results show that:(1) when the platform cooperates with general component suppliers, the bargain power of platform is stronger, and the institutional logic of platform occupies a dominant position; (2) when the platform is dependent much on the bottleneck component supplier, the bargaining power of complementor is stronger, and the platform has to compromise in the cooperation between the two parties. At this time, the institutional logic of complementor dominates; (3) when the relationship between the platform and the bottleneck component supplier is bidirectional dependence, the institutional logic formed by the two parties' cooperation is hybrid logic; (4) in the face of strong external institutional pressure, the cooperation between the platform and complementors will form or follow the new institutional logic.

Key words: platform, innovation ecosystem, complementor, institutional logic