With the increasing emphasis on sustainable investment, ESG rating results have become an important reference for investors to make decisions, but at present, the rating results of ESG rating agencies exist wide divergence around the world. How will such divergence affect the information environment of capital markets? To this end, this paper takes China’s A-share listed companies from 2015 to 2021 as samples, uses the rating results of four rating agencies, SynTao Green Finance, Hexun, Rankins CSR Ratings and Bloomberg, to construct an ESG rating divergence measurement index, and empirically tests the relationship between ESG rating and stock price synchronization. The research finds that ESG rating divergence significantly improves the stock price synchronization of rated companies. It indicates that there is a "noise effect" in the ESG rating divergence. The conclusion is still valid after a series of robustness tests. Further research shows that the positive impact of ESG rating divergence on stock price synchronization is that it intensifies the market information asymmetry. When the information environment of listed companies is better and investors have strong information interpretation and analysis ability, the "noise effect" caused by ESG rating differences can be alleviated. The conclusions of this paper provide policy suggestions for regulators to standardize ESG rating standards and promote the pricing efficiency of capital markets.