China's environmental regulations are increasingly strengthening, green innovation has become the main path for enterprises to solve environmental difficulties and achieve sustainable development. Using data samples from manufacturing listed companies in Shanghai and Shenzhen from 2012 to 2021, this study empirically investigates the relationships among environmental regulations, R&D investment and green innovation of enterprises. The results indicate that the impact of environmental regulations on green innovation of enterprises shows a U-shaped trend of inhibition followed by promotion, and R&D investment can positively regulate the impact of environmental regulations on green innovation of enterprises. Further research has found that environmental regulations have a dual threshold effect on the impact of green innovation in enterprises; the impact of environmental regulations on green innovation in enterprises includes regional heterogeneity, property heterogeneity, and industry heterogeneity, and the regulatory effect of R&D investment also has the same heterogeneity. Therefore, it is necessary to synergistically promote environmental protection and economic development, strengthen the dual environmental responsibility of the government and enterprises, and enhance the public's awareness of environmental protection, rely on big data technology to improve the quality and efficiency of environmental supervision, fully consider the heterogeneity of environmental regulations and formulate differentiated environmental policies to fully leverage the policy effects of environmental regulations.