Taking the “Environmental Protection Tax Law of the People's Republic of China” implemented in 2018 as an exogenous impact, and taking the data of manufacturing listed enterprises and provinces from 2015 to 2020 as samples, whether environmental regulation could promote the improvement of corporate financial performance was explored. The results are as follows.Environmental regulation has a significant effect on corporate financial performance,and it improves financial performance by stimulating enterprises to carry out technological innovation. Heterogeneity analysis finds that the promotion is more remarkable for non-state enterprises and enterprises in the eastern region. These are helpful to understand the internal mechanism between the two, and strong empirical evidence for promoting the coordinated development of ecology and economy are put forward.