The invention discloses a wave energy converting device attached to a bulwark. Multiple functions of wave absorbing, wave resisting, power generating and the like are combined, due to the fact that the wave energy strike from which the bulwark is suffered throughout the year is greatly reduced, the service life of the bulwark can be greatly prolonged, and electric power generated by the wave energy can be directly supplied to equipment in the bulwark to be used. The wave energy converting device is simple in installing form, no substantive change is achieved for the existing bulwark technology, the wave energy converting device is easily combined with the existing bulwark technology, and therefore the wave energy converting device has wide application prospects and high economic value and is worthy of application and popularization.