AbstractCollaborative innovation among different stakeholders is essential for the successful implementation of megaprojects. As collaborative innovation challenges in megaprojects are complex to foresee and plan, previous research adopted mediated power (i.e., contracts) to understand the coordination process in traditional construction projects, which may not be applicable to explain collaborative innovation in megaprojects. This study explores the role of perceived partners’ non-mediated power (expert and referent power), shared mental models, and team creative efficacy in improving collaborative innovation performance based on organizational identification theory and social cognitive theory. We surveyed 490 managers of Chinese construction megaprojects and used the SPSS PROCESS Macro mediation model and hierarchical multiple regression to test our research hypotheses. Results showed that perceived partners’ expert power and referent power positively affect participants’ collaborative innovation performance via dual-mechanism: shared mental models and team creative efficacy. Findings also demonstrated that identification with partners enables megaprojects participants to voluntarily coordinate the innovation activities of others and to participate in their innovation activities by developing a cohesive cognitive structure and boosting innovation confidence. These findings enrich the theory of megaprojects innovation management and provide suggestions for how megaprojects partners can make informed decisions to foster participants’ collaborative innovation.