Abstract With the continuous development of social economy, cable lines account for an increasing proportion of urban power supply networks. Because the discharge location is usually under the soil layer when a cable faults, it is necessary to locate the fault first before it can be repaired. This article combines six 10kV medium voltage cross-linked polyethylene cable faults, analyzes the waveform data through the low-voltage pulse method, the flash method and the secondary pulse method, and conducts a preliminary distance measurement of the fault point; and uses the acousto-magnetic synchronization method to accurately locate the fault location. Finally, the fault part of the cable is dissected, and the specific cause of the fault is analyzed to provide a basis for the safe and stable operation of the medium-voltage cable terminal in the power system.