A major issue is whether the implementation of China’s green credit policy will affect the coordinated development of corporate sustainable operations and environmental protection. This paper used a propensity score matching—difference-in-differences (PSM-DID) model to analyse the impact of China’s green credit policy implemented in 2012 on the maturity mismatch risk between investment and financing in polluting and non-polluting companies. We found that: (1) green credit policies can help reduce the risk of maturity mismatch between investment and financing for polluting companies; (2) the reduction of short-term bank credit is the main way to curb the risk of maturity mismatch risk between investment and financing; (3) the green credit policy has no obvious mitigation effect on the risk of maturity mismatch between investment and financing among polluting companies with environmental protection investment; (4) the mitigation effect of the green credit policy on the maturity mismatch risk is more significant in state-owned polluting companies and polluting companies in areas with a lower level of financial development. The empirical results show that China’s green credit policy helps stimulate the environmental protection behaviour of companies, as well as helping alleviate the capital chain risk caused by the maturity mismatch between investment and financing. In addition, despite the effect of heterogeneity, it can solve the contradiction between environmental protection and economic development.