The invention provides a power generation device utilizing ocean wave energy. The power generation device comprises a piezoelectric energy harvesting device arranged on a levee. The piezoelectric energy harvesting device comprises piezoelectric structure units. Each piezoelectric structure unit comprises an arched copper plate. A plurality of piezoelectric films are mounted inside each piezoelectric structure unit. The two ends of the piezoelectric energy harvesting device are fixed on a sliding rail through connecting rods. The piezoelectric energy harvesting device is connected to a power source control device through a wire so as to output power energy. By utilizing the power generation device, damage of waves to the levee can be relieved, the life is prolonged, spontaneous power energy supply can be also obtained, energy resource waste is reduced, and great economic benefits are obtained.