a b s t r a c tZnO-Pr 6 O 11 based varistor ceramics doped with 0-2.0 mol% SnO 2 were fabricated by sintering samples at 1300 • C for 2 h with conventional ceramic processing method. X-ray diffraction analysis indicated that the doped SnO 2 reacted with praseodymium oxides during sintering, generating Pr 2 Sn 2 O 7 phase. Through scanning electron microscopy, it was found that the doping of SnO 2 played a role against the growth of ZnO grains. Capacitance-voltage analysis revealed that the doped SnO 2 acted as a donor in the varistor. The measured electric-field/current-density characteristics of the samples showed that the varistor voltage increased with the increase of SnO 2 doping content, when the SnO 2 content was no more than 1.0 mol%; with the SnO 2 content up to no more than 0.5 mol%, the doping of SnO 2 could increase the nonlinear coefficient; but, when the SnO 2 doping content was further increased, the nonlinear coefficient and varistor voltage of the samples decreased, and the leakage current increased.