Water flow power generation device

The utility model provides a water flow power generation device which comprises a mounting platform, a rotating mechanism, a tower drum, a cabin, a generator, a gearbox and an impeller, wherein the mounting platform is positioned on a water surface, the rotating mechanism is arranged on the mounting platform, and the tower drum is positioned in water. The upper end of the tower drum is fixed on the rotating mechanism, the generator and the gearbox are arranged on one side of the cabin, the impeller comprises a hub and a plurality of blades, a center shaft of the hub is connected with the generator through the gearbox, wheel rings sleeve telecentric ends of the blades far away from the center of the hub and are of cylindrical structures with hollow side walls, buoyancy obtained by the impeller in the water counteracts the weight of the impeller by the aid of the hollow structures of the wheel rings, so that the weight of the impeller is zero, the mounting platform is fixed on a suspension frame comprising a buoy, and the suspension frame fixedly floats on the water surface through a pull rope and a ground anchor. The impeller does not need to overcome the weight of the impeller under impact of water flow and rapidly rotates, and work obtained by rapid rotation is completely converted into power for power generation, so that power generation efficiency is greatly improved.