Green technology innovation is imperative to sustainable and environmentally sound economic development and is currently facing increasingly serious environmental threats. However, existing research has overlooked the uncertainties in economic policies. Based on the logical relationship between environmental regulation, economic policy uncertainty, and green technology innovation, this study empirically analyzed the quantitative relationship among these three variables using the xed-effect panel method and provincial panel data from 2000 to 2017 for 30 administrative regions of China. The results show that environmental regulation is positively correlated with green innovation, whereas economic policy uncertainty has a negative in uence on green innovation, thereby regulating the relationship between the remaining two factors. Moreover, considerable regional heterogeneity exists in these causal in uences, i.e., environmental regulation promotes green innovation in the eastern and middle regions but not signi cantly in the west. The uncertainty actively moderates the impact of environmental regulation on green innovation in all regions with an adjustment coe cient of approximately 0.8; however, it inhibits green innovation in different degrees, especially in the eastern and middle regions. Based on empirical results, we conclude that strict and appropriate environmental regulations are necessary and effective in China to encourage green technology innovation, especially in regions with uncertain economic policies.