The invention relates to a borehole operation tool, and specifically relates to a reverse circulation sand washing device. The reverse circulation sand washing device comprises a barrel; during sand washing, a sand washing solution passing through the middle of the barrel and the sand washing device is used for impacting the barrel so as to form a sand mixing solution; the sand mixing solution enters into a sand washing passage under the guide of a guide plate; a part of the sand mixing solution in the sand washing passage directly passes through a first filter so as to enter into a sand washing pipe column, and the part of the sand mixing solution is used for taking away tiny impurities; the other part of the sand mixing solution is used for taking large impurities into a crushing cavitythrough holes in a partition board; large sand enters into the crushing cavity along the radial direction of the barrel and collides with crushing teeth inside the crushing cavity; after the tiny impurities are formed by crushing the large sand, the small impurities enter into the sand washing pipe column through a second filter, so that the large impurities inside the sand mixing solution are crushed through the crushing cavity; and therefore, the sand washing device is avoided from being blocked by the impurities, repeated cleaning of the sand washing device is avoided, and the sand washingefficiency is improved.