Abstract: There is an interactive relationship between regional market integration and environmental governance. The higher regional integration of the Yangtze River Delta is inseparable from the improvement of regional environmental governance. This thesis uses the spatial simultaneous equation model and GS3SLS method to analyze the interaction mechanism between market integration and urban environmental governance. The results show that there is a significant interactive influence and mutual promotion between market integration and urban environmental governance, but the market integration in the Yangtze River Delta plays a greater role in promoting urban environmental governance. However, the spatial interactive effect is significantly negative between market integration and urban environmental governance in the Yangtze River Delta. Therefore, in order to improve market integration in the Yangtze River Delta, it is necessary to accelerate the formation of a regional unified large market, innovate the ways for environmental governance to participate in regional market integration in the Yangtze River Delta, and promote the coordination between market integration and environmental governance in the Yangtze River Delta.