The utility model discloses a vehicle-mounted equipment earthing detection device, which comprises an earthing potential detection unit, a logic identification unit, a status display unit and a power supply circuit, wherein the signal input end of the earthing potential detection unit is electrically connected with the power supply of detected equipment and the earthing terminal of the detected equipment; the signal input end of the logic identification unit is connected with the signal output end of the earthing potential detection unit; the signal output end of the logic identification unit is connected with the signal input end of the status display unit; and the power supply circuit supplies power to the logic identification unit and the status display unit. According to the vehicle-mounted equipment earthing detection device disclosed by the utility model, the statuses of directly earthing, tyre earthing (poor earthing), unearthing and the like of the vehicle-mounted equipment can be distinguished so as to guarantee the personal safety of workers and the safe maintenance of instrument equipment. The vehicle-mounted equipment earthing detection device can be widely applied to the field of the vehicle-mounted equipment earthing detection.