The invention discloses a protecting device for a wave-energy power generating device. The protecting device comprises the wave-energy power generating device, an air inlet and water inlet pipe is arranged in the middle of the wave-energy power generating device, one end of the air inlet and water inlet pipe is connected with a hose, the other end of the air inlet and water inlet pipe is arranged in an air inlet and water drainage cabin which is arranged at the bottom of the wave-energy power generating device, a floating mat is arranged at the other end of the hose, floating balls are arranged all around the floating mat through connecting parts, floating balls and wind power generators are arranged on the upper surface of the floating mat, and a power conversion and power collection device is arranged in the floating mat; and drainage pipes are arranged on the air inlet and water drainage cabin, two fixing blocks are connected to the bottom of the air inlet and water drainage cabin through fixing block anchor chains, and multiple stabilizing blocks are arranged at the bottom of each fixing block. The protecting device for the wave-energy power generating device has the advantages of being capable of being suitable for bad weather, capable of better utilizing wind energy under bad weather and achieving multiple power generating modes, higher in safety and longer in service life.