The invention provides a method for reducing the Al2O3 inclusion content in a semi-steel steelmaking billet. The method comprises the steps that an anthracite recarburizing agent is added to molten steel for deoxygenation firstly; an aluminum wire is then added to the deoxidized material so that deoxygenation can continue, and deoxidized molten steel is obtained; and the deoxidized molten steel is cast to obtain the steel billet. Compared with the prior art, the method for reducing the Al2O3 inclusion content in the semi-steel steelmaking billet, the molten steel is subjected to primary deoxygenation with the anthracite recarburizing agent firstly, the aluminum wire is then adopted for further deoxygenation on the molten steel, no aluminum-iron alloy is required for deoxygenation of the molten steel, and through cooperation of the anthracite recarburizing agent and the aluminum wire, the Al2O3 inclusion content in the deoxidized molten steel is reduced while a great deoxygenation effect is ensured. The Al2O3 inclusion content in the steel billet prepared from the molten steel with low Al2O3 inclusion content is also reduced.