The invention discloses a fan blade special for a power generating device applied to a region rich in tidal energy, and belongs to the field of tidal power generator fan blades. The fan blade specialfor the power generating device applied to the region rich in tidal energy solves the problem that too high tidal energy damages a tidal power generation device through the structure. When the tidal energy is in a moderate state, tidal energy impacts on a current limiting end, the current limiting end and an additional panel are rushed out of a movable sliding groove, the stress area of a whole fan blade body is increased, and the utilization efficiency of the fan blade body on the tidal energy is improved; when the tidal energy is too high, the addental panel can be further pushed out of themovable sliding groove, a pressure relief hole is exposed, and the too high tidal flow can penetrate through a drainage through groove, the movable sliding groove and the pressure relief hole and directly penetrate through the fan blade body; and the loss caused by the too high tidal flow to the fan blade body is reduced, the construction cost of a tidal power station is greatly reduced, the maintenance cost of a tidal power generation device is reduced, and normal operation of the tidal power station is easily kept.