Abstract: High-voltage power cables are considered as important transmission and transformation equipment, and the monitoring and analysis of the metal sheath grounding current are regarded to be of great significance for the safe and stable operation and fault early warning of high-voltage power cables. The overvoltage and induced voltage of the metal sheath are first introduced to elaborate the research results of the influencing factors of the grounding current. Secondly, the control of the grounding current and the cable defect identification based on the grounding current data are elaborated. Then, the technical advantages and disadvantages of the online monitoring of the grounding current are elaborated. Finally, the pain points of the online monitoring technology are analyzed through the elaboration of a typical case where a defect is successfully warned by the online monitoring, so that technical references are provided for high-voltage power cable engineering and technical personnel.