The motor drives the rotor to move at a very high speed. The blow bar is installed around the rotor, and used to crush material. When the material goes into the area which the blow bar effects, under the impact function of the blow bar at a high speed, the materials are thrown to the impact device continuously, and then the materials are rebounded from the impact device to the area of blow bar to be crushed again. The material in the impact chamber are to be crushed repeatedly. The process goes on until the material are crushed to the required size and the discharged from outlet.