Epoxy resin has been widely used in electrical and electronic information fields due to its excellent insulation and economic performance. The nanoparticles-adulterated epoxy can enhance its insulation properties, including the dielectric strength, the corona resistance, the tracking resistance, the thermal conductivity, the low temperature resistance, the radiation resistance and the weather resistance. In this paper, the research progress of epoxy resin nanocomposites is discussed in detail, including the doping of different kinds of nano-particles such as silica, titania, alumina, magnesia, etc. to improve the dielectric properties and space charge behavior of epoxy resin, and the influence mechanism of the interface region in the nanocomposite dielectrics is analyzed. The method of surface modification of nanoparticles and its influence on the electrical insulation properties of epoxy composite dielectric are analyzed.