Developments in power capacity have made arc grounding overvoltage increasingly prominent. This paper proposes a new method for determining current-voltage (I-V) characteristics of ZnO nonlinear resistance on a new grounding mode, by analyzing the power system through the symmetrical component method, considering system capacities, operation mode, and other characteristics. Then, the I-V characteristics of ZnO nonlinear resistance are obtained through the segmental linearization method. Finally, a model based on an actual 10kV system is established, and the different grounding modes are compared and simulated by ATP-EMTP. Results indicate that the designed ZnO nonlinear resistance parameters can suppress arc grounding overvoltage, and the proposed grounding mode is safe and reliable.