Taking the Stock Connect scheme as an exogenous shock based on data of China’s Ashare non-financial listed companies from 2009 to 2021, we identify the causal effect of stock market liberalization on green innovation. The baseline result based on a staggered difference-indifferences (DID) model suggests that stock market liberalization promotes corporate green innovation and this effect is similar to the green benefits of China’s mandatory environmental regulations. The results are robust to various checks, including the parallel trend tests, placebo tests, and the heterogenous time-varying treatment test based on Bacon decomposition and the DIDM approach. The enhanced continuity of corporate financing, improved corporate green governance and increased firm external technological collaboration are three plausible channels that allow stock market liberalization to promote corporate green innovation. Moreover, the effect is more significant for clean firms, non-SOEs, and firms in a good institutional environment. Further analysis suggests that the green innovation-enhancing effects of stock market liberalization are more likely to be high-quality innovation. Our paper provides new insights into understanding the green benefits of stock market liberalization and achieving sustainable economic development in developing countries.