<p>This study systematically investigated the differences in mechanical properties, slag corrosion resistance, and oxidation resistance of MgO-C refractories incorporated with two types of anti-oxidants, namely silicon (Si, labeled as S) and silicon carbide (SiC, labeled as SC) powders. The corrosion characteristics of MgO-C refractories exposed to slags with low basicity were also analyzed. After high-temperature heat treatment at varied temperatures, sample SC possessed higher mechanical strength than sample S. Owing to the relatively low oxidation rate of SiC powder, sample SC presented inferior oxidation resistance and a wider transition zone. In addition, the reaction between Si powder and graphite led to the formation of a porous microstructure in the matrix. Consequently, the matrix of sample S suffered severe slag erosion and structural damage. Overall, sample SC exhibited superior resistance to slag penetration and corrosion compared with sample S. Thermodynamic simulation results revealed that slag basicity regulated the content and viscosity of the liquid phase generated during high-temperature reactions, which further caused distinct differences in the slag penetration resistance of the two refractories. Notably, sample SC achieved the optimal slag penetration resistance at a slag basicity of 1.5.</p>