Vibrating screen is working by using the reciprocating cibrating generated by the vibrator excitation . The reciprocating’s upper rotary hammer can make the screen produce a recycling vibrating. And the lower rotary hammer can make the screen produce a recycling vibrating . Their combination can make the whole screen to vibrate repeated. Its vibrating orbit is a complication space curve. Such curve’s projection into horizontal is a round shape while it is a ellipe shape when projection in vertical direction . To adjust the upper and lower ‘s rotary hammer ‘s exciting force can change the amplitude. If adjust the upper and lower rotary hammer’s space degree ,it can change the screen’s movement obrits.