By analyzing the motion state of rape extractions on vibration sieve in different ejection intensities and based on the collision theory a motion mathematical model of a rapeseed on the vibration sieve was established. By analyzing the major factors affecting the motion state and motion stability of rapeseed the motion regularity of rapeseed with different ejection intensities was found. Experiments were conducted on experimental platform to find out the influence on the cleaning loss ratio which caused by the changing ejection intensity. The influence on the ejection intensity which caused by the motion parameters was analyzed. These results provide reference basis for selecting the motion parameters of vibration sieve on cleaning device.