Abstract: Environmental regulation is a policy combination that restricts the pollution behavior of enterprises, and plays a role in protecting the ecological environment in the process of regional development. In this paper, the Undesirable-SBM model, coefficient of variation, Gini coefficient, trend test analysis method and panel Tobit model are used to analyze the spatial-temporal evolution characteristics and influencing factors of the environmental regulation efficiency of the three major urban agglomerations in the Yangtze River Economic Belt from 2009 to 2018. The research shows that:（1) The different stages of urban development in the Yangtze River Delta urban agglomeration lead to differences in environmental regulation efficiency. The lack of coordination at the end of the Chengdu-Chongqing urban agglomeration causes a significant difference in environmental regulation efficiency. The difference in environmental regulation efficiency in the middle reaches of the Yangtze River is small, but the level Lower than other urban agglomerations;（2) The “economic-ecological” coordinated development of urban agglomerations in the Yangtze River Delta, the efficiency of environmental regulation has increased significantly. The agglomeration is a low-efficiency urban agglomeration zone, and the deteriorating cities are as high as 45.16%;（3) There is a certain room for improvement in the input and output of the three major urban agglomerations, which need to be improved in terms of capital allocation, policy input, and pollutant end treatment. ;（4) The impact of economic development on the efficiency of environmental regulation of urban agglomerations is positive, and the impact of industrial structure, urbanization level, and the level of opening to the outside world have different effects on the efficiency of environmental regulation. This study provides the decision-making basis for the three major urban agglomerations to develop and implement differentiated environmental policies and measures to promote the sustainable development of the urban agglomerations in the Yangtze River Basin. It can also provide lessons for other regional environmental governance.