Promoting a green transformation of development mode is crucial, with technological support playing a key role. Based on data from China's A-share listed companies in western regions from 2011 to 2020, this study empirically analyzes the nonlinear relationship between government subsidies and corporate green innovation, as well as the moderating effect of accounting information quality. The findings reveal a positive U-shaped relationship between government subsidies and corporate green innovation, initially declining and then rising. Effective promotion of corporate green innovation is achieved only when government subsidies reach a certain critical threshold, with a more significant effect observed for state-owned enterprises. The analysis of moderation effects further indicates that in high accounting information quality contexts, the positive U-shaped relationship between government subsidies and corporate green innovation is significantly strengthened. Moreover, for state-owned enterprises, non-specific subsidies are more effective in stimulating green innovation beyond the critical threshold. These research findings provide theoretical foundations and practical insights for the formulation of relevant innovation incentive policies by the government and the promotion of corporate green innovation.