The paper collects panel data of 30 provinces in China from 2003 to 2022, using DDML models and panel threshold models. It is found that, firstly, both environmental regulation and green innovation can drive green economic growth in bidirectional effectively, and there is positive and effective interactive spillover effect between them. Secondly, during the process of increasing environmental regulation intensity, the elasticity coefficient of the impact of green innovation on green economic growth exhibits a ∩ shaped evolutionary characteristic from rising to falling. Reversely, during the process of enhancing green innovation capabilities, the spillover effect of environmental regulations on green economic growth has changed from insignificant to positively significant, and shows a dynamic spillover law of marginal increase in higher intervals. Finally, the interactive spillover effect of environmental regulation and green innovation on green economic growth exhibits spatial heterogeneity, the optimal spillover threshold for environmental regulation intensity shows the distribution characteristics of higher in the east regions, and lower in the west regions. While the optimal spillover threshold for green innovation capability shows the distribution characteristics of higher in the middle regions, and lower in the east regions.