In view of an investigation of the impact of environmental regulations on the performance of listed companies, a Difference-in-Difference (DID) model has thus been constructed by using companies listed on the A-share market in China from 2011 to 2022 as research samples and the implementation of the new Environmental Protection Law as a quasi natural experiment. It is found that the new Environmental Protection Law can significantly promote corporate performance of listed companies, and this conclusion still holds true after a series of robustness tests. A further exploration of the mechanism test shows that the new Environmental Protection Law incentivizes the corporate performance improvement by alleviating the pressure of external financing pressure on enterprises. A heterogeneity analysis indicates that the new Environmental Protection Law can significantly enhance the performance of growing and large-scale enterprises, while it is relatively weak in its impact on the performance of maturing and small-scale enterprises.