A refueling gun comprises a housing, a valve rod, and a handle. A pump body is provided within the housing, the pump body is connected to an oil intake pipe and an oil outlet pipe, and a first check valve is provided within the oil intake pipe; an end portion of the valve rod located in the pump body is connected to a negative pressure generating assembly comprising a disk, a plurality of limiting members, and a sealing ring; the disk is fixedly connected to the end portion of the valve rod; the sealing ring is sleeved on the periphery of the plurality of limiting members, the sealing ring is slidingly connected to an inner wall of the pump body and is sealingly connected to the inner wall of the pump body; and the handle is rotatably provided on the housing and is connected to the valve rod.