As environmental issues grow increasingly complex and multifaceted, the synergistic effects of environmental policies and their implementation methods have become central to the environmental policy system. This paper analyzes panel data from all A-share-listed companies in China between 2013 and 2022 and aims at comprehensively evaluate the role and impact of command-and-control, market-incentive, and public-participation environmental policies along with their combinations on corporate green transformation by using a double machine learning method. The results indicate that (1) all three types of environmental policies positively influence corporate green transformation, with market-based policies having the most pronounced effect; (2) the synergistic effects of policy combinations further enhance corporate green transformation, especially the combination of market-incentive and public-participation environmental policies; (3) heterogeneity analysis highlights differences in the effects of these environmental policies and their combinations on corporate attributes and regional factors; and (4) mechanism analysis indicates that green innovation and financial constraints indirectly drive the high-quality green transformation of enterprises.