Based on panel data from China's A-share listed companies from 2012 to 2023, this paper employs a difference-in-differences model to empirically examine the impact of green finance policies on the low-carbon transition of high-carbon enterprises, with a specific analysis of the heterogeneity between high water-consuming enterprises and general water-consuming enterprises. The findings indicate that green finance promotes the low-carbon transition of high-carbon enterprises. Furthermore, due to the water-energy nexus, high water-consuming enterprises exhibit greater sensitivity to the low-carbon transition effects of green finance policies. Robustness tests confirm the reliability of the policy effects, underscoring the pivotal role of green finance policies in advancing the transition towards a low-carbon economy.