The invention belongs to the field of utilization of 
renewable energy, and provides a wave-energy generating device for generating power through 
water potential energy. The device comprises a water absorbing tank, a water storing tank, a water absorbing 
pipe, a water draining 
pipe, a 
piston, a sealing ring, a floating block, a hinge pin, a supporting platform, and a water draining port in the upper part of the water absorbing tank. The device is characterized by further comprising a pressing rod, a 
turbine generating device in the water absorbing 
pipe, a 
turbine generating device in the water draining port, a baffle switch hinged to the 
piston, a baffle switch hinged to the water absorbing port, a filtering net and a 
water pipe fixing rack, wherein the pressing rod and a rack achieve a lever effect, and the floating force and 
gravity effect of the wave to the floating block can be amplified to act to the 
piston. According to the water-energy generating device, the pressing rod can drive the piston to reciprocate, and the baffle switch hinged to the piston and the baffle switch hinged to the water absorbing port play supporting roles, so as to achieve the purposes of absorbing water and draining water; meanwhile, the 
turbine generating devices in the water absorbing pipe and the water draining port of the water storing tank are correspondingly driven to generate power during the water absorbing process and the water draining process; array manners are combined to use, so that the wave energy can be utilized well, and the purpose of continuously generating power can be achieved. The device is of an opening structure, is influenced a little by the environment, and is simple in structure, and convenient to maintain and replace a part.