Spiral sand washing machine is suitable for construction sites, sand and gravel plants, hydropower stations, concrete dam sites,post and telecommunications pole factories. The sand washing machine is arranged at an inclination of 15°, and the lower part of the water tank is surrounded by three side slabs to form a sedimentation tank. The spiral head is not inserted into the sedimentation tank, and the spiral is continuously rotated by the electric motor through the reducer, and the washing water is fed from the perforated plate at the bottom of the sedimentation tank. The device has three functions of cleaning, dehydration and classification.