The screw sand washing machine uses different particle size and density of particles to have different sedimentation speeds in the fluid. The particles with fine particle size and small density have a slow sedimentation rate, while the particles with large particle size and high density have a fast sedimentation speed, and the dust and The impurities are separated from the sand, and under the uniform agitation of the spiral, the purpose of filtering the water to remove impurities and lifting the transportation is achieved. The spiral sand washing machine has the advantages of a long spiral body, good sealing system, simple structure, strong processing capacity, convenient maintenance, and high washing rate. The spiral sand washing machine is widely used in highways, railways, municipal construction, stone factories, construction sites, concrete prefabrication yards. And a large amount of sand and gravel de-sludge operations by hydropower, and it can also be used for washing, grading and dewatering sand.