Water treatment system and treatment method for treating high-sand-content source water

The invention relates to a water treatment system and method for treating high-sand-content source water. A precipitation part carries out precipitation treatment on raw water to be treated and conveys the raw water to an advanced treatment part, a regulating reservoir and a construction production line; the advanced treatment part carries out advanced treatment on the precipitated water to obtain construction domestic water; the regulating reservoir stores the precipitated water, and when the precipitated water conveyed to the construction production line is not enough to meet the production water demand, conveys the stored precipitated water to the construction production line; and by arranging the regulating reservoir, a certain amount of precipitated water is stored in the regulating reservoir under the normal condition, and in the flood season, the precipitated water in the regulating reservoir is used as a supplementary water source for construction and production, so that the construction and productio