The invention belongs to the field of building coating production, and particularly discloses a building coating ingredient grinding device. The building coating ingredient grinding device comprises abox body, an upper grinding plate and a lower grinding plate are fixedly connected to the inner wall of the box body in sequence from top to bottom, the sides, close to each other, of the upper grinding plate and the lower grinding plate are each provided with a conical installing port, an upper grinding cone is arranged in the conical installing port of the upper grinding plate, a lower grindingcone is arranged in the conical installing port of the lower grinding plate, and the sides, close to each other, of the upper grinding cone and the lower grinding cone are planes; and limiting grooves are symmetrically formed in the top side of the lower grinding cone, limiting rods are slidably installed in the limiting grooves, and the top ends of the two limiting rods extend to the exterior ofthe limiting grooves and are symmetrically and fixedly connected to the bottom side of the upper grinding cone. According to the building coating ingredient grinding device, the structure is novel, use is convenient, the grinding precision of building coating ingredients can be adjusted, the ingredients can be dried and then can be conveniently ground, and therefore the production efficiency is improved.