Using panel data of Chinese manufacturing enterprises listed in Shanghai and Shenzhen A-shares from 2015 to 2021, we examine the effects of heterogeneous environmental regulations on the green transformation of Chinese manufacturing enterprises under "Double Carbon" target, and reveal the mediating role played by managers' green perception in the process from an intra-firm perspective. We find that three environmental regulation tools, namely environmental administrative supervision, environmental economic regulation and environmental soft constraint, all contribute significantly to the green transformation of manufacturing enterprises. Among them, environmental economic regulation is the most effective in promoting the green transformation of manufacturing enterprises, followed by environmental soft constraint and environmental administrative supervision. The mechanism analysis shows that managers' green perception is partially mediated between heterogeneous environmental regulations and the green transformation of manufacturing enterprises. Moreover, environmental administrative supervision is the most effective in raising managers' green perception among them, followed by environmental economic regulation and environmental soft constraint. Further analysis shows that the positive effect of heterogeneous environmental regulations on the green transformation of Chinese manufacturing enterprises is more significant when the enterprises locate in regions with high policy uncertainty, in the eastern part of the country, or when the enterprises are state-owned enterprises. The conclusions provide a theoretical basis for Chinese environmental policymakers to flexibly adopt differentiated environmental regulation tools.