A method of preparing R—Fe—B-based rare earth magnetic powder for a bonded magnet and magnetic powder prepared thereby, and a method of manufacturing a bonded magnet using magnetic powder and a bonded magnet manufactured thereby. Further, a method of preparing R—Fe—B-based rare earth magnetic powder having improved magnetic properties including grinding rare earth sintered magnet products as a raw material, performing a hydrogenation process where a ground product is charged into a furnace, and the furnace is then filled with hydrogen and a temperature of the furnace is increased, performing a disproportionation process where the temperature of the furnace is further increased in the same hydrogen atmosphere above, performing a desorption process where hydrogen is exhausted from an inside of the furnace, and performing a recombination process where hydrogen in the inside of the furnace is exhausted, and magnetic powder prepared thereby, and a method of manufacturing a bonded magnet.