Based on the data of A-share listed companies from 2010 to 2019, this paper finds that environmental regulation increases the debt risk of enterprises, and financing constraints have a mediating effect on the relationship between environmental regulation and corporate debt risk. Based on the differences in the nature of property rights, it is found that the negative effect of environmental regulation on corporate debt risk is more significant in non-public enterprises. This paper enriches the research on the impact of environmental regulation on corporate debt risk, provides empirical evidence for enterprises to prevent debt risk from the perspective of environmental supervision, and is of great significance for strengthening the effect of government environmental regulation and preventing corporate debt risk.