Abstract: The doping of rare earth elements can significantly improve the voltage gradient (E_1mA) of ZnO varistors, whereas it will lead to an increase in the leakage current, thereby reducing the aging stability of ZnO varistors. In order to solve the problem of increasing leakage current caused by doping rare earth elements, the influences of Y₂O₃, Ga₂O₃ and B₂O₃ co-doping on the microstructure and electrical properties of ZnO varistors were studied in this paper. The doped Y₂O₃ can significantly inhibit the growth of ZnO grains and increase the E_1mA of the sample through the pinning effect. The doping of Ga₂O₃ helps to increase the barrier height (φ_b) of the grain boundary layer and restrain the increase of leakage current density (J_L).The doping of B₂O₃ is helpful to improve the liquid phase sintering of the sample and avoid the occurrence of Y spinel phase aggregation with high resistivity, and the blocking of the transmission channel is beneficial to reduce the J_L of the sample. In addition, the doping of B₂O₃ can promote the ion exchange between ZnO grains and other additives at the grain boundary, so that φ_b can be effectively improved and its J_L can be further reduced. In this paper, ZnO varistors with relatively excellent comprehensive performance were obtained by co-doping Y₂O₃, Ga₂O₃ and B₂O₃, of which the voltage gradient (E_1mA) is 466 V/mm, the leakage current density (J_L) is 0.41 A/cm², and its nonlinear coefficient is 95. The successful development of high gradient and low leakage ZnO varistors is of great significance for solving the problem of uneven distribution of the overall potential of metal oxide arrester.