The utility model provides a locomotive positioning system based on a rail circuit and a DGPS. The locomotive positioning system comprises a ground device and a vehicle-mounted device. The ground device comprises a DGPS base station, a tracking and positioning server, a communication server, an interlocking state collecting server, a 3G base station and a plurality of tracking and positioning client sides. The vehicle-mounted device comprises a vehicle-mounted positioning host, a 3G data transmitting unit, a DGPS module, a displayer, a sensor set, a vehicle row detector and a plurality of electronic hanging connectors. By means of the locomotive positioning system, the locomotive position detecting accuracy and precision can be improved, and powerful and accurate data sources are further provided for optimizing the scheduling strategy.