It based on the different setting velocities of barley and impurities, the washing machine can separate impurities including Bingjian Stone in the similar size with barley. The de-stoning procedure is omitted. Therefore, the cost is reduced. The environmental dust is controlled efficiently in the process of de-impurity process so that the working environment is improved, meanwhile, during the cleaning process the barley has received water's pre-soap which will contribute to the germination effect.