Within the context of Carbon Peaking and Carbon Neutrality objectives, reducing carbon emissions and improving energy-environmental efficiency have emerged as the primary concerns of China’s environmental governance. It will become increasingly important to study how environmental regulation can improve the environmental efficiency of energy. First of all, this study uses the non-radial distance function method to measure the energy-environmental efficiency of 30 provinces in China from 2011 to 2020. Secondly, this study uses the generalized moment estimation model to test the relationship between the two. Furthermore, in order to better clarify the transmission mechanism between environmental regulation and energy environmental efficiency, this study uses the intermediary effect model to conduct an empirical test. Finally, in order to explore the spatial distribution relationship of energy-environmental efficiency, this study conducts an exploration based on the spatial regression model. It has been observed that: (1) The average energy-environmental efficiency in China exhibits “high in the east and low in the west” distribution characteristics, and the energy-environmental efficiency fluctuates steadily all the time. (2) Environmental regulation can effectively enhance regional energy-environmental efficiency. (3) Industrial upgrading and technological innovation are essential mediating mechanisms of environmental regulation for energy-environmental efficiency. (4) The energy-environmental efficiency of each province has a significant positive spillover effect. Environmental regulation not only plays a significant role in promoting regional energy and environmental efficiency, but also plays a positive role in promoting energy and environmental efficiency in neighboring areas. Consequently, this study puts forward specific suggestions to improve China’s energy-environmental efficiency through environmental regulations.