The invention discloses a multistage washing sand washer which comprises a storage hopper, a first sand washing groove, a sand washing device and a second sand washing groove. An outlet of the storage hopper is located above the first sand washing groove. A first spiral blade is arranged inside the first sand washing groove and installed on a first rotating shaft. One end of the first rotating shaft is connected with an output shaft of a first motor. A water inlet is formed in the first sand washing groove. The first sand washing groove and the sand washing device are connected through a feeding belt. A discharging outlet of the sand washing device is located above the second sand washing groove. According to the multistage washing sand washer, multistage treatment can be performed on sand, soil blocks of the large size and other impurities are decomposed through the first sand washing groove into sand of the small size, then, the sand enters the sand washing device, most impurities inside the sand washing device are separated out and separated out with sand washing water, and finally the small number of remaining impurities are separated out through the second sand washing groove, so that the product quality is ensured.