The invention relates to a deoxidation method for reducing Al2O3 impurities in aluminum killed steel, and belongs to the technical field of metallurgy. The method solves the technical problems that alarge amount of aluminum-iron alloy needs to be added in the aluminum killed steel making process, the production cost is high, and the content of the Al2O3 impurities in a cast blank is high. According to the technical scheme, the deoxidation method for reducing the Al2O3 impurities in the aluminum killed steel comprises the following steps that semi-molten steel serves as a raw material, the oxygen activity of molten steel is controlled by a converter smelting end point to be 500-700 ppm, the carbon content is 0.05-0.08%, the end point temperature is 1660-1680 DEG C, 1.8-2.5 kg of calcium carbide is added into each ton of steel in a steel ladle in the tapping process, a small platform behind a converter furnace is used for oxygen determination, and 0.48-1.91 kg of aluminum wires are added into each ton of steel according to the oxygen activity condition of the molten steel. The method is suitable for deoxidation treatment in the production process of the aluminum killed steel, a large quantity of Al2O3 impurities are avoided, and the deoxidation cost of the converter furnace is reduced.