When bucket sand washer works, motor drives the impeller to rotate slowly through triangle belt, reducer and gear wheel after deceleration. Sand and gravel enter the washing tank from feeding trough, where they roll and grind each other under the impeller’s driving force, removing impurities covered on sand and gravel surface. Meanwhile the water vapor layer covering the sand particle is destroyed to facilitate dehydration. Simultaneously, water is added to create a strong water flow, which can promptly remove impurities and small foreign objects with low specific gravity. These impurities are discharged from the outlet of the washing tank, completing the cleaning function. The clean sand and gravel are taken away by the blades and poured into the discharge trough from the rotating impeller, completing the sand cleaning process. The sand processed in sand washer is clean and uniform in particle size. It is easy to operate and maintain and has good safety performance.