There are problems of inaccurate measurement of ground parameters and difficulty in selecting high resistance grounding fault lines in resonant grounding systems. Thus this paper proposes a new method for measuring ground parameters and selecting high resistance fault lines in parallel damping resonant grounding systems. Based on the switching characteristics of parallel damping resistance of an arc suppression coil, the system’s ground conductance and capacitance parameters are measured by using the relationship between the zero-sequence voltage amplitude and phase change before and after switching the damping resistor. During normal operation of the system, the zero sequence admittance value of each feeder line is measured by adjusting the parallel damping resistance value. After a ground fault occurs, the damping resistance is exited and the zero sequence admittance value of each feeder after the fault is measured. This can eliminate the influence of system parameter asymmetry and asynchronous transformer sampling, actively construct the zero sequence admittance phase difference of each feeder before and after the fault, and achieve accurate identification of the faulty line. The proposed method is validated in the PSCAD simulation environment, and the results show that it can accurately measure the ground conductivity and capacitance parameters, with a relative measurement error of no more than 0.6%; when grounding faults occur in different feeders and transition resistors, the fault line can be accurately identified, and the resistance to transition resistance can reach 10 k.