The nonlinear electrical properties and degradation behavior against an impulse-current of 400 A in the ZnO-Pr6O11- CoO-Cr2O3-Y2O3-Er2O3 (ZPCCYE) varistors were investigated with different Y2O3/Er2O3 ratios. The Y2O3/Er2O3 mole ratio has a significant effect on nonlinear electrical properties and impulse degradation behavior of the ZPCCYE varistors. The varistors added with Y2O3/Er2O3=0.5/0.5 exhibited the best nonlinear properties with 39 in nonlinear coefficient (α) and the best clamp characteristics, in which the clamping voltage ratio (K) was in the range of K=1.62-2.18 at an impulse-current of 1-50 A. The varistors added with Y2O3/Er2O3=0.25/0.5 exhibited the best electrical stability, with %ΔE1 mA/cm 2=-5.6%, %Δα=6.7%, and %ΔJL=-14.6% against an impulse-current of 400 A. On the contrary, the varistors added with Y2O3/Er2O3=0.5/0.5 were destroyed applying an impulse-current of 400 A.