When the XSD series sand washing machine is working, the motor drives the impeller to rotate slowly through the V-belt, reducer, and gear. The sand and gravel enter the washing tank from the feeding trough, tumble under the drive of the impeller, and grind each other to remove the covering sand and gravel. The impurities on the surface will simultaneously destroy the water vapor layer covering the sand particles to facilitate dehydration; at the same time, water will be added to form a strong water flow, which will promptly take away the impurities and foreign objects with small specific gravity and discharge them from the overflow outlet washing tank to complete the cleaning effect. The clean sand and gravel are taken away by the blades, and finally poured into the discharge trough from the rotating impeller to complete the cleaning effect of the sand and gravel.