The damage and failure of the dielectrics seriously affect the further improvement of the transmission voltage level and capacity. The quantum chemical calculation method takes electrons as the research object. The band structure, trap distribution, and various physical and chemical parameters of the insulating medium can be obtained through calculation, which greatly enriches the theoretical system of dielectrics. In this paper, the quantum chemical calculation and density functional theory are introduced. In addition, in order to address the high power and integration needs of power equipment, nano-doping by quantum chemical calculation methods are reviewed in this paper. In summary, quantum chemical calculation methods have become an important part of the “insulating material design” system. This method helps to better understand the dielectric behavior of insulation and grasp the mechanism of insulation failure. Meanwhile, the quantum chemical calculation method also provides an effective means for the development of new DC insulation materials and provides scientific support for the development of “Computational High-Voltage Engineering”.