The housing is fixed with a wave-receiving device and at least one power generation device, and the housing is connected to the observation buoy by a connecting line. The present useful new medium power generation device includes a housing, a wave receiving device and a power generation device, the wave receiving device comprises a wave receiving plate, a base and a central shaft rod; When it is  working, the receiving plate moves relatively under the action of the waves, and the wave energy is converted into electrical energy output through the periodic shock of the piezoelectric device.