Taking the green credit policy in 2012 as a quasi-natural experiment, this paper applies the methods of propensity score matching and Difference-in-Difference (PSM-DID) to investigate the relationship between green credit policy and enterprises’ green technology innovation performance based on Chinese industrial enterprises database and green patent database. The results show that the implementation of “green credit guidelines” policy has significantly improved the green innovation performance of high-polluting and high-energy consuming enterprises, which indicates that the incentive effect of green credit policy on enterprises exceeds the constraint effect and leads to “Porter effect.” Moreover, the green credit policy has significantly increased the number of non-invention patents rather than invention patents. In addition, the green credit policy has a more significant effect on the green innovation performance of high-polluting and energy-intensive enterprises that are state-owned and have weak market power. Mechanism test shows that green credit policy can change the credit financing constraints and R&D investment allocation to affect the green innovation performance of high-polluting and energy-intensive enterprises.