The invention discloses an anti-collision device for a bridge pier. The anti-collision device comprises an inner buffering cushion, a rotating assembly and an outer anti-collision assembly which are coaxially arranged from inside to outside. The pier is tightly wrapped by the inner buffering cushion, the outer anti-collision assembly can rotate around the axial central line through the rotating assembly, the rotating assembly comprises an inner ring, an outer ring and spherical rolling bodies evenly distributed between the inner ring and the outer ring, the outer ring can rotate relative to the inner ring, and the inner ring can be matched with the inner buffering cushion in a relatively rotating mode. Not only can the aims of prolonging stress time and reducing impact force borne by the pier be achieved through the outer anti-collision assembly, but also the outer anti-collision assembly can rotate around the axial central line through the rotating assembly when the pier is impacted, so that the impact force caused by objects of ships and the like is guided to shift away from the pier, the remaining huge impact force after buffering of the outer anti-collision assembly is shifted away as much as possible, and safety of a bridge is greatly improved. In addition, the inner ring of the rotating assembly further can rotate relative to the lateral face of the outer circumference of the inner buffering cushion to generate a secondary rotating effect, and the effect of shifting the impact force away from the pier is further improved.