Abstract: Environmental regulation is the sum of the policy measures implemented by the government and the restrictive effects of social organizations and the public on the emission behavior of the main bodies of pollution discharge in order to prevent and control environmental pollution and improve the environmental quality. There are various forms of environmental regulation. The definition and connotation of environmental regulation had been controversial in academic circles, and the characterization of environmental regulation intensity would directly affect academic research results and decision-making behavior. Based on the literature review of environmental regulation at home and abroad, the proposer, essence, purpose and function of environmental regulation were analyzed, and the characterization methods of environmental regulation intensity were summarized. At the same time, the research content of environmental regulation literature was summarized which was divided into two fields, i.e. social environmental effect and economic effect of environmental regulation, and its research application was reviewed. Finally, according to the results of literature review, a new interpretation of the definition of environmental regulation was given.