In 2018, China launched the environmental protection tax (EPT) policy. To measure the impact of this policy, we used this event as a quasi-natural experiment and empirically analyzed the impact of this new policy on corporate green innovation. By analyzing the quantity and quality of green innovation, we find that this new tax policy can significantly improve the quality of innovation. At the same time, we excluded the influence of company size on our conclusion and find that the new policy has a positive impact on the quality of green innovation (GI) in both large-scale and small-scale company. Finally, we also find that the implementation of policies contributes to the improvement of ESG ratings.