The invention discloses a sand grinding tool of ultrathin fireproofing water-based paint. The sand grinding tool of the ultrathin fireproofing water-based paint comprises a sand grinding inner cylinder, a sand grinding outer cylinder, a sand grinding feeding port, a cooling water inlet pipe, a cooling water outlet pipe, an outlet cylinder, a sand grinding discharge port, a sand grinding shell, sand grinding machine bottom feet, a sand grinding motor, a sand grinding motor belt pulley, a sand grinding shaft belt pulley, a sand grinding belt, a sand grinding shaft, a fixed abutting disc, sand grinding discs, a connecting block, a movable abutting disc, a turbulent motor, a turbulent base, turbulent claws and turbulent convex blocks, wherein the sand grinding motor is arranged on one side ofthe top surface of the sand grinding shell, the sand grinding shaft is transversely arranged in the sand grinding inner cylinder, the sand grinding discs are fixedly connected with the sand grinding shaft, the connecting block is arranged between the two sand grinding discs, the movable abutting disc is fixedly connected with a movable shaft, and one end of the turbulent motor extends into the sand grinding inner cylinder and is fixedly connected with the turbulent base. According to the sand grinding tool, the number of the sand grinding discs can be increased and decreased, the distance between the sand grinding discs can be adjusted, meanwhile, a plurality of kinds of turbulent structures are adopted, so that raw materials are kept in a high-efficiency sand grinding state in a sand grinding cylinder, and the sand grinding efficiency, speed, and precision is high.