Although research on green innovation has increased dramatically in recent years, little is known about the system mechanisms for the innovation. Grounded in the resource dependency theory (RDT) and national innovation system (NIS) literature, this study examines the ecosystem in promoting green innovation from both theoretical and empirical perspectives. This study constructs a Nash-Cournot equilibrium to address the effects of national green innovation systems on corporate green innovation. Using data of 2136 A-share listed enterprises, 31 provincial-level R&D data, and 329 prefectural-level government annual work reports in China, this study finds that corporate collaboration, government subsidies, regional university R&D intensity, long-term credit, and government attention enhance the number of green innovation patents and patent diversity. Government attention strengthens the positive effects of corporate R&D cooperation, government subsidies, R&D intensity of regional research institutions, and long-term credit on the number of green innovation patents.