As a crucial component of the financial system, it is of profound practical significance to explore whether the environmental credit system (ECS) can effectively facilitate the green transformation of pollution-intensive enterprises. Taking the "Enterprise Environmental Credit Evaluation Measures (Trial)" in 2014 as an event, we utilize green behavior and green evaluation as proxy variables of green transformation and employ the difference-in-difference (DID) method to analyze the influence of the ECS on the green transformation of pollution-intensive enterprises. The findings are as follows: The ECS promotes the green behaviors of pollution-intensive enterprises, enhances their green evaluations, and propels their green transformation. Moderation effects analysis reveals that regional green financial development enhances the reinforcing effect of the ECS on green behaviors and evaluations, whereas negative environmental events detract from the facilitative effect on both. Additionally, regional environmental governance amplifies the positive influence of the ECS on green behavior, and environmental certification reinforces its role in promoting green evaluations. Further research discovers that corporate green behaviors and evaluations enhance corporate finance performance and alleviate financial constraints. This study offers empirical evidence and practical suggestions to perfect the ECS and facilitate the green transformation of pollution-intensive firms.