The invention discloses an automatic speed change slag removal machine. The automatic speed change slag removal machine comprises a motor, a speed changer, a belt, a rotary cleaning roller box, a rack and a base. The motor is connected with the speed changer, and the motor and the speed changer are arranged on the base through a support. A rotary wheel I on a rotary shaft is driven to operate by the motor, a rotary wheel II is driven to operate by the rotary wheel I through the belt, and the rotary cleaning roller box is driven to rotate by the rotary wheel II through a transmission shaft. The rotary cleaning roller box is arranged on the rack, the rack is arranged on the base, and a circular steel cleaning pillar is welded into the rotary cleaning roller box. The automatic speed change slag removal machine is simple in structure, easy to operate, small in occupied area and wide in application range; during actual use, the automatic speed change slag removal machine can clean surface residues of parts in an electric transmission line angle-steel tower and a power transformation structure frame, wherein the parts need surface residual cleaning, the residues comprise the welding soldering flux residues, the ferric oxide residues generated after the parts are cut and the like; and the cleaning effect is good, safety and reliability are achieved, and working efficiency is improved.