The invention discloses a polishing method for a gallium antimonide single crystal wafer. For coarse polishing, a cerium oxide polishing pad is adopted, and polishing liquid contains aluminum oxide abrasives with the particle size of W1, at the pressure of 100 to 200 g/cm<2>, the rotating speed of 10 to 40 r/min and the flow of 10 to 50 mL/min; for medium polishing, a black polyurethane polishing pad is adopted, and the polishing liquid contains silicon dioxide nano abrasives with the particle size of 60 to 100 nm and an oxidant, i.e., sodium hypochlorite, at the pressure of 80 to 150 g/cm<2>, the rotating speed of 60 to 100 r/min and the flow of 10 to 30 mL/min; for fine polishing, a black synthesized leather polishing cloth is adopted, and the polishing liquid is abrasive-free polishing liquid, at the pressure of 30 to 100 g/cm<2>, the rotating speed of 20 to 60 r/min and the flow of 5 to 10 mL/min. The polishing process is simple and easy to operate; the gallium antimonide single crystal wafer is low in surface damage and easy to clean, and the surface roughness is 0.3 nm.