Abstract: Defects in the cross-bonded grounding system seriously threaten the safe and stable operation of cable lines. Currently, such defects can only be diagnosed under the condition of power outages, resulting in long power outages and grid risk duration. Therefore, it was decided to develop an energized defect diagnosis device for cross-bonded grounding system of power cable, to reduce the diagnosis time of a cross-bonded unit to less than 1.5 hours. The device includes a collection part, a host part, and a terminal part. Through scheme selection and countermeasure implementation, the device has been completed. Effect check showed that the device had achieved the goal of reducing the diagnosis time to less than 1.5 hours per unit, with significant safety, social, management, and economic benefits.