The sand and mud mixture is transported to the cyclone, and the centrifugally classified and concentrated washed sand is supplied to the vibrating screen through the sand nozzle. After being dehydrated by the vibrating screen, the washed sand and water are effectively separated. A small amount of washed sand and mud are returned to the cleaning chamber through the return box. When the liquid level in the cleaning tank is too high, it will be discharged through the outlet port to complete the cleaning, dehydration and particle size classification process of sand washing.