With the increasing attention to environmental protection, flexible voluntary environmental regulation has aroused extensive discussion. Using the 3432 Chinese A-share listed companies as research samples from 2008 to 2020, we explore the relationship between voluntary environmental regulation and the risk of the stock price crash, and the moderating effect of media attention. We find that voluntary environmental regulation can effectively reduce stock price crash risk, which supports the Porter hypothesis. The media attention further enhances the negative relationship between voluntary environmental regulation and stock price crash risk. We further consider the nature of corporate property rights and find that voluntary environmental regulation can better help state-owned companies reduce stock price crash risk, while the impact on non-state companies is not significant. In addition, we divide the media attention into positive and negative categories, and the results show that both positive and negative media attention positively mediate the negative relationship between voluntary environmental regulation and stock price crash risk. Our conclusions confirm the Porter hypothesis and provide some implications for policymakers to optimize environmental regulation.