Digital finance has realized the efficient allocation of financial resources and provided new opportunities for heavy polluting enterprises to achieve green transformation. Based on the panel data of 723 Shanghai and Shenzhen A share listed companies in China’s heavy polluting industries from 2011 to 2021, this paper empirically analyzes the impact of digital finance development on green investment of heavy polluting enterprises and its transmission mechanism. The research results confirm that: the development of digital finance can significantly improve the level of green investment in heavy polluting enterprises, and this conclusion is still valid after passing a series of robustness tests. The mechanism test results show that digital finance can improve the level of green investment in heavy polluting enterprises by mitigating financing constraints and inhibiting corporate financialization. In the further analysis, environmental regulations and analyst attention positively regulate the promotion effect of digital finance on green investment of heavy polluting enterprises; digital finance only has a significant effect on the level of green investment of Chinese enterprises and large-scale enterprises in heavy polluting industries. Finally, based on the research findings, relevant suggestions are proposed to promote the development of digital finance and green investment of enterprises.