Al4SiC4 was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to study its effect on the oxidation resistance, apparent porosity, bulk density, elastic modulus, and modulus of rupture. It is found that Al4SiC4 can be synthesized by microwave sintering at 1 300 ℃ and the addition of Al4SiC4-containing material as an antioxidant can enhance the oxidation resistance of the magnesia carbon refractory brick.