Deepening the reform of state-owned enterprises and accelerating the development of the mixed ownership economy has become the highlights of the new round of state-owned enterprises reform. Based on the data of A-share listed companies in China from 2007 to 2015, this paper uses the exogenous events of privatization to compare the environmental performance of state owned enterprises and private enterprises on the basis of solving the endogenous problems. The results show that after the privatization of state-owned enterprises, the performance of the corporate environment has deteriorated. However, increasing environmental subsidies and improving environmental regulation will reduce this negative impact. This paper examines its impact on the environmental performance of enterprises, which is of great significance for further deepening the privatization reform of state-owned enterprises and further improving the corporate governance of privatized enterprises.