The carbon emission reduction of enterprises is not only related to their own long-term development, but also important to the realization of China’s “double carbon” goal. Using the sample of A-share manufacturing listed companies in Shanghai and Shenzhen stock markets from 2009 to 2021, and the publication of third-party ESG rating in the capital market as a quasi-natural experiment, we employ the multi-period difference-in-differences (DID) method to investigate the impact of the ESG rating soft regulation on carbon emissions intensity of listed enterprises. The results of the study indicate that soft market regulation of ESG rating is helpful to reduce carbon emission intensity of enterprises. The impact mechanism test shows that soft market regulation of ESG rating influences corporate carbon emission intensity mainly through increasing media attention and inhibiting managerial myopia. Moderating effects show that the divergence of ESG rating will weaken the carbon intensity governance effect of ESG rating. The above relationship is more significant in samples with stronger environmental regulations and high ownership by institutional investors. Soft regulation of ESG rating also reduces carbon emission intensity by other companies in the same industry and city, showing some spillover effects. The research conclusions not only enriches and expands the literature and research perspectives on the regulation of ESG rating in capital market and corporate carbon emission intensity, but also provides useful inspiration for improving the regulation of ESG rating in capital market and promoting corporate carbon emission reduction more effectively.