Abstract: In order to optimize the distribution system, selecting the proper neutral point grounding method is one of the most important methods to improve the reliability and economical efficiency of the distribution network. Therefore, the selection and application of the neutral point grounding method is to improve the operation level of the distribution system. The key factor. This paper analyzes and establishes a simulation calculation model to study the single-phase earth fault current and over-voltage characteristics in the arc suppression coil grounding, low-resistance grounding, arc suppression coil, and low-resistance grounding methods of the distribution network neutral point 66kV system; Impact on personal safety, and reliability of power supply in case of failure. The application principle of neutral point grounding method for 66kV system and the effectiveness and applicability of different capacitive current testing methods are proposed to improve the safety of the urban 66kV system power grid.