Green innovation is crucial to achieving the objective of sustainable development. The efficient allocation of financial resources made by digital finance provides new green innovation opportunities for heavily polluting enterprises. Using panel data from Chinese A-share listed enterprises in heavily polluting industries, this paper constructs zero-inflated negative binomial regression model to examine the impact of digital finance on green innovation of these enterprises. The results show that digital finance positively impacts green innovation in heavily polluting enterprises, and the breadth of coverage and depth of usage can significantly promote green innovation relative to the degree of digitization. Corporate human resource management has a partially mediating effect, which is evident as digital finance promotes green innovation by optimizing the structure of high-educated and high-skilled personnel in heavily polluting enterprises; regional industrial structure upgrading plays a masking effect that slightly offsets the direct promotion of green innovation to digital finance, but the advanced industrial structure still markedly enhances the level of green innovation in heavily polluting enterprises.