ZnO-based varistors with different doping levels of antimony and bismuth are prepared and their electrical properties are measured. It is found that when the doping level of Sb is small，with the amount of Sb2O3 increasing，the leakage current changes little，both nonlinear coefficient αL and breakdown nonlinear coefficient αB decrease but both field strength EL and breakdown field strength EB increase; when the doping level of Sb is high，with more Sb2O3 added，the leakage current increases sharply，αL and αB decrease further，and EL and EB drop down suddenly. With doping level of Bi increasing，the leakage current increases，αL and αB increase，but EL and EB decrease.