The utility model relates to a power supply flatcar which comprises a flatcar frame used for bearing components. A motor, a speed reducer, a main wheel set and a driven wheel set are arranged at the bottom of the flatcar frame, the power supply flatcar further comprises a power supply device, the power supply device is a battery pack arranged in a battery mounting frame which is fixedly connected with the flatcar frame, and the battery pack can be a storage battery pack or a lithium battery pack; a charging device is further arranged on the power supply device and comprises a first charging seat mounted on one side of the flatcar and a second charging seat mounted on a flatcar parking end point, the first charging seat is a round moving contact, the second charging seat is a plate-like fixed contact, and when the flatcar is parked, the two charging seats make contact for automatic charging; a rail cleaning device is further arranged, and when the flatcar moves, impurities on rails are removed. According to the power supply flatcar, cables are omitted, potential safety hazards caused by dragging of cables are avoided, automatic charging is achieved at idle hours, and the power supply flatcar is convenient to use, stable in operation and safe and reliable, and saves energy.