Combined with spraying roller, overflow tank, beans absorber, rotating water segregator. Beans transported by the elevator into the washer hopper, then enter the washing barrel, through the helical mixer, the dust and the microorganism on the surface will be eliminated, and the sand will be filtered out. When the beans into the roller from the overflow tank, the impurity floating on the water will automatically flow out. The beans will be absorbed into the rotating water segregator from the overflow tank bottom, and the water flow with the beans and impurity will rotate from the top to bottom in the segregator, the sandstones, metal and sincere beans with larger centrifugal force will deposit at the bottom along with the inner wall, and the beans with smaller centrifugal force will enter the bean-soaking tank along with the internal whirlpool under the preset suction. By the processes above the beans can be segregated with the impurity thoroughly, so the impurity can be eliminated.