Abstract: In this paper, accuracy of experimental testing was verified through estimating floatation velocity of material. Movement equation and dynamic equation of cereal were established in air-stream. With the optimization and analysis by Visual Basic 6.0 on the basic experimental testing and movement equation and dynamic equation, the effects of initial velocity of cereal and air-stream velocity on cereal movement loci and separation distance were studied. Results were suggested that the factors of the cleaning performance effect significante order were air-stream velocity, air stream velocity angle, initial velocity and initial velocity angle, their optimum ranges were developed.