The invention discloses a device for preventing blocking of a draining well of a tailing pond. The device comprises a plastic ring (2) placed on the outer periphery of the wall (1) of the draining well (6) and a buoy ring formed by multiple buoys (4) connected into a whole; a gap is formed between the plastic ring and the wall (1) of the draining well (6), so that it is guaranteed that the plastic ring can go up and down freely with the water surface; the buoy ring surrounds the outer periphery of the plastic ring (2), support rods (3) are outwards installed on the plastic ring (2) at intervals, and the outer ends of the support rods (3) are connected with the buoy ring; the distance between the buoy ring and the wall (1) of the draining well (6) is 1-2 m. The device surrounds the periphery of the draining well and can go up and down with the water level simultaneously, so that the blocking phenomenon caused by floaters entering the draining well is effectively prevented and treated; mounting and dismounting are convenient, the maintenance and repair costs are not needed at all, and the service life is long.