Various types of flammable and explosive gases exist in the working stratum of mines. When electricity leakage occurs from an electrical appliance in the mine, it is easy to cause safety production accidents of underground explosions. Therefore, leakage faults should be detected and handled in time to ensure coal mine safety. The low-voltage power supply system of Lu'an Wangzhuang Mine was taken as the research object, the special data processing method of electric leakage fault was studied, and the least square method data processing method can accurately process the electric leakage data signal.