When material enters into the crusher, it can be crushed by the ring hammer which is revolved by the high-speed motor, at the same time material obtained the kinetic energy and rushed at the impact plate receiving the second crushing process, then falls on the screen sieve and be cut, extruded, and grinded by the ring hammer. At last the materials that come up to the standard can be discharged by the machine. Material can’t be crushed enters into the metal collector and should be eliminated regularly. Through replacement of sieve plate, discharge size of materials can be adjusted. Gap between rotor and sieve plate can be adjusted by the mechanism.