In the context of public policy aimed at enhancing the overall effectiveness of the national innovation system and building a globally competitive open innovation ecosystem, the problem of enhancing the effectiveness of innovation ecosystems has attracted increasing attention from the academic community. This paper, using a coevolutionary perspective, explores the mechanism of coevolution at the micro- and macro-levels in an open innovation ecosystem. Based on this, using qualitative research methods, it interprets the key driving mechanisms for enhancing the effectiveness of an open innovation ecosystem in the Chinese context and analyzes effective ways to enhance systemic effectiveness.