Using the data of listed companies and the DID method, this paper reveals three ways in which green credit policy (GCP) affects corporate debt financing. By controlling credit input, GCP can effectively restrain corporate debt financing in the “two-high” industries. However, the policy also leads to the environmental performance effect and bank credit discrimination effect, as it strengthens the impact of environmental performance on corporate debt financing and weakens banks’ credit discrimination. Under the combined effect of the three ways, GCP has restrained the borrowing growth of state-owned enterprises, but has no significant impact on private firms.