From the perspective of behavioral finance, China's A-share listed companies in Shenzhen and Shanghai from 2007 to 2019 are taken as the research objects in this paper, and various influences of different sources, degrees and types of board overconfidence on the risk of stock price crash are empirically tested. Further research finds that the corporate supervision mechanism has an inhibitory effect on the stock price crash risk caused by different types of overconfidence, but most of them are not significant, indicating that the governance effect of the corporate supervision mechanism is limited. The research results presented in this paper can provide a reference for China to establish a perfect capital market provision system and carry out a regulatory reform.