MOV (metal oxide varistor zinc) are often applied in pressure limiting type SPD (surge protector) in the form of multi-chip parallel, because its performance will directly affect the overall protective effect of the device, then analyse zinc oxide varistor in parallel multi-chip methods and its performance. According to the theoretical analysis of electrical characteristics of parallel varistors, the main reason of current deviation is that the limit voltage and dynamic resistance are not equal. Based on the electromagnetic transient analysis of software ATP-EMTP at the same time, considering MOV voltage characteristics of the whole region and the corresponding characteristics of current role of the large current, building the circuit model, using 8 / 20μs pulse current loop and 2ns rise rate of the square wave loop measurement, simulating the residual pressure and flow characteristics under different number of pieces MOV to obtain variation trends after multi-chip parallel MOV residual pressure flow-through, and then giving the best parallel relative number of pieces.