Based on the panel data of 30 provinces in China from 2005 to 2017 and on the construction of the green economy efficiency measurement index system, this paper uses the super-efficient DEA model to measure national green economy efficiency considering undesired output. The system GMM model analyzes the impact of environmental regulation on the efficiency of the green economy. The results show that from the national sample, the relationship between environmental regulation and green economic efficiency has a “U” shape. When the environmental regulation intensity is kept within a certain “critical point”, its impact on the efficiency of green economy has inhibition, but if this strength exceeds this “tipping point”, its impact is promoted. From the sub-samples of the three regions, the environmental regulation of the central and western regions has an inhibitory effect on the efficiency of the green economy, the impact of environmental regulation on the eastern region is promoted, and the eastern characteristics are the same as the national empirical analysis. The remarkable “U” relationship can be found to be more effective in improving the efficiency of the green economy in economically developed regions.