Abstract: When the low-voltage DC system is grounded, it needs to be found in time. If the search equipment used is complex in structure and complicated in operation, it is not convenient for promotion and application. This paper presents a device for finding the grounding fault point of low-voltage DC system. The utility model has the advantages of simple structure, easy learning and use, convenient operation, high safety and reliability. After being put into use, professional relay protection personnel are no longer required to find the grounding. The operator can find the grounding point of low-voltage DC system. It saves a lot of human resources, vehicles and other materials. The more important thing is to find out and eliminate the grounding fault in time, so as to improve the safety and reliability of the power system.