Epoxy resin has many excellent properties and is widely used in various fields. However, it is increasingly difficult for solvent-based epoxy resin to meet the requirements of environmental protection in the market. Therefore, it is quite important to seek water-based epoxy resin. In this paper, the preparation methods of water-borne epoxy resin emulsions such as mechanical method, reverse conversion method, chemical modification method and curing agent emulsification method are introduced in detail. The principle and process of various methods are systematically described, and the important factors affect of water-borne epoxy resin is analyzed and summarized. In addition, the advantages and disadvantages of different preparation methods are described in detail, and the optimization and improvement directions are prospected. The latest research progress of water-borne epoxy resins at home and abroad was reviewed. It was pointed out that the development trend of water-borne epoxy resins in the future was the selection of production formula, optimization of process flow and planned functional modification, which broadened the application of waterborne epoxy coatings.