Abstract: A locomotive-mounted power battery pack fire safety control system includes a power battery pack, a power battery management system main controller, a rolling stock microcomputer system and a rolling stock display screen. The power battery pack is an enclosed installation isolated from external air. An inert gas injection pipe, a smoke detector and a temperature detector are arranged at the top end inside the power battery pack. An inert gas storage device is arranged outside the power battery pack. The inert gas storage device is connected with the inert gas injection pipe. A pressure detector and an inert gas injection control switch are arranged in turn on a pipeline through which the inert gas storage device discharges an inert gas to the power battery pack. The pressure detector and the inert gas injection control switch are connected with the rolling stock microcomputer system.