Abstract: SnO₂ varistor doped with SiO₂ of different mole fractions (0.01%, 0.05%, 0.10%, 0.15%, 0.20%) was prepared by traditional method. The effect of SiO₂ doping amounts on the electrical performance of SnO₂ varistor was studied. The results show that with the increase of SiO₂ doping amounts, the voltage gradient, nonlinear coefficient, barrier height, donor density and interfacial state density of SnO₂ varistor first increased and then decreased, the leakage current density first decreased and then increased, and the grain boundary resistance increased. When the mole fraction of SiO₂ was 0.10%, the SnO₂ varistor had the best comprehensive electrical performance, with the largest voltage gradient, nonlinear coefficient, donor density, interfacial state density and the barrier height, and the smallest leakage current density, which were 582 V·mm^-1, 33, 1.7×10²³ m^-3, 6.7×10¹⁶ m^-2, 2.03 eV, 7.06 μA·cm^-2, respectively.