Abstract: Based on the homemade oat harvester, the test bench of the cleaning device was designed. The revolving speed of its main and the secondary centrifugal fan, and the frequency of vibrating sieve were tested as influencing factors. The ratios of impurity and loss were used as indicators. Based on these elements, the bench test was carried out. the range of values for each factor is determined by single-factor experiment. the regression model is established by the multiple regression experiment, the optimal combination of parameters calculated by MatLab was 1439 r/min of the main centrifugal fan, 1796 r/min of the secondary centrifugal fan and 5.9 Hz of the frequency of vibrating screen. The relevant ratios of impurity and loss were respectively 1.30% and 0.82%. after experiments, these optimal parameters were credible. Field test was carried out using the best parameter combination, the grain impurity ratio was 1.30% and the loss ratio was 0.82%, the device had good cleaning performance and met the actual harvesting requirements.