With the development and popularization of the concept of sustainable development, more and more investors have begun to use corporate ESG performance to measure the long-term development ability of enterprises, but due to the existence of different evaluation systems among different rating agencies, which has led to the emergence of ESG rating divergence. Against the background of widespread ESG rating divergence, this paper aims to investigate the impact of ESG rating divergence on the level of stock mispricing in the capital market. Through empirical research, it is found that, first, the greater the corporate ESG rating divergence, the greater the level of stock mispricing; second, this paper examines the path of the impact of ESG rating divergence on the level of stock mispricing. The findings show that the expansion of ESG rating divergence promotes the stock mispricing level by reducing the rational investor-institutional investor shareholding path. Meanwhile, when the nature of corporate ownership is state-owned enterprises, the more depressed investor sentiment, and the worse corporate ESG performance, the stronger and more significant the contribution of ESG rating divergence to the level of stock mispricing. Finally, this paper demonstrates the robustness of the research findings by the method of replacing the evaluation indicators of ESG rating divergence and stock mispricing level. This study not only confirms the negative impact of ESG rating divergence on the capital market, but also provides ways and means to improve the pricing efficiency of the capital market.