Abstract: Oats have been paid more and more attention because of their high nutritional value and economic benefits. In view of the inconsistency of grain maturation in the same plant caused low maturity of grains is difficult to desquamate, so the content of grains with skin (shell) is high, which affects the harvest quality and subsequent processing. The oat-grains are strong and tough, are not easy to break, this paper according to the special characteristics of oat-grains, combined with the advantages of rubbing resistance, put forward a scheme to purify oat-grains. The scheme used the advantages of strong toughness and rubbing resistance to rub and remove the shell (peel) of the oat-grains first, then cleaned the grains with negative pressure clearance. It could avoid the disadvantages of miscellaneous surplus and separate the grain easier. This paper used the principle of rubbing grain peel (shell) and negative pressure clearance, designed a high degree of clarity and low loss oat grain purification device to solve the problem of high clutter content of oat grain caused by the large grains with shell. The device used a vertical conical rubbing roller to rub and treat the miscellaneous residues of oat leather grain and so on, and used the negative pressure cleaning room to clear and remove the clutter in the oat grain. The device could achieve the high cleanliness and low loss result, improve the quality of oat grains harvesting, and avoid the loss of grains, finally achieved the goal of increasing harvest yield and improving grain quality. In this study, the factors affecting including the speed of rubbing roller, the air speed of miscellany expert and the bezel length were analyzed and screened, and the clean ratio and loss ratio were used as the evaluation indicators. A single factor test was carried out to determine the range of optimal values for each influencing factor, and multivariate regression test was carried out on the basis of the single factor test. The multivariate regression model of test factors and evaluation indicators were established and solved, and the response surface analysis of the influence of 2 factors on the evaluation index was processed. The parameter values after optimization were validated. The test results showed that the single factor affecting the performance index of the device was 700-900 r/min of the roller speed, the air speed of miscellany expert was 12-16 m/s, the bezel length was 15-25 cm. The multivariate regression test results in a better combination of parameters: the roller speed was 816 r/min, the air speed of miscellany expert was 13.8 m/s, the bezel length was 20.5 cm, then the clean ratio of the index was 99.23% and the loss ratio was 1.53%. When the optimization parameter combination condition was pressed, the verification test results were trusted within the allowed test error within 3%. This study provides a reference and experimental basis for improving the technical level of oat harvesting machinery in China and the development of subsequent oat food processing machinery.