Abstract: This study focuses on research question “How do enterprises with focus on innovation ecosystem overcome collective uncertainty and build complementary resources?” Through a comparative analysis of Geely and Xiaomi, this study closely follows the situational elements of the innovation ecosystem, and deconstructs and analyzes the two types of uncertainties of ‘subject dimension’ and ‘functional dimension’ in the process of resource complementation in the context of the innovation ecosystem. Secondly, it is found that the two resource complementarity strategies of knowledge base expansion and ecological goal renewal based of adapting strategic posture, and system knowledge definition and complementarity relationship guidance based on the shaping strategic posture which help focal firm overcoming the uncertainty in the process of resource complementarity. This research develops and integrates the analytical framework of ‘collective uncertainty of innovation ecosystem-strategic posture choice-resource complementary mode choice’, and depicts the unique path for enterprises to overcome uncertainty and establish resource complementary in the context of innovation ecosystem.