Provided is a mechanical transmission three-wheel dump car lifter, belonging to the technical field of transmission devices. The mechanical transmission three-wheel dump car lifter includes a power casing, a double-end spline shaft, an inner-tooth spline shaft, a power small bevel pinion, an inner-tooth drum, a rising large bevel gear, a rising small bevel gear, a screw rod, a nut, a lifting cylinder, a support top, a positioning pin, left and right support plates, a positioning pull board, and a connecting shaft, the double-end spline shaft is connected with the inner-tooth spline shaft, a power large bevel gear is engaged with the power small bevel pinion, the rising large bevel gear is engaged with the rising small bevel gear, the screw rod is engaged with a sleeve nut in the rising small bevel gear, the lifting cylinder support top is connected to the middle hole of the connecting shaft support plates, and a left hole hinge clamp is connected with a container. The mechanical transmission three-wheel dump car lifter can be arranged on a mechanical dump car and an electric car to realize the self-unloading of the container.