A cooling system for a shafting and a control method therefor, and a wind turbine are provided. The cooling system includes a cold air supply unit and a rotating-shaft air blow box. The rotating-shaft air blow box is mounted on an inner surface of the stationary shaft and in the shape of a circular ring-shaped box, multiple first air blow openings are uniformly distributed in a surface, facing the rotating shaft, of the rotating-shaft air blow box in a circumferential direction, to blow cold air from the cold air supply unit to the rotating shaft. Each first air blow opening is in the shape of a slit to form a jet.