Abstract: Grounding system defects such as lead seal cracking and water inlet oxidation are one of the main causes of cable joint failures, especially in the environment of frequent geological settlement and high groundwater level in Hangzhou, potential hazards of the poor grounding system of high voltage cables are particularly prominent. The traditional testing methods, such as the charging detection of sheath circulation and the circuit resistance outage detection, are limited by the blackout period and the wiring mode of the grounding box, and there are still blind areas. In recent years, State Grid Hangzhou power supply company introduced the grounding circuit resistance live detection method, in the case of live grounding system circuit resistance test, through more than 3 600 field tests, in the case of traditional live detection methods were showed to be normal, found and eliminated hidden defects more than 30 of the grounding system, effectively improving the health of Hangzhou main network cable grounding system.