The invention provides a propeller of a water flow generator, solves the technical problem that an existing winding preventing device is poor in cutting effect, and relates to a propeller winding preventing device. The propeller winding preventing device comprises a fixed seat, wherein the fixed seat is matched with a transmission shaft of a propeller in a linkage manner; the cross section of the fixed seat is H-shaped; a plurality of groups of blades are arranged on the fixed seat oppositely and vertically; and center lines of the blades which are distributed vertically in the same group are not positioned on the same axis. Through the fixed seat which is matched with the transmission shaft in the linkage manner, the staggered blades which are arranged in the peripheral direction of the fixed seat are used for cutting, an existing mode of cutting stationary knives by using movable knives is avoided, a linkage rotating mode is adopted, moreover, the blades are fixed firmly, the circumstance of breakage of the blades is avoided, and the cutting effect can be good.