MgO-SiC-C refractories demonstrate distinguished thermal shock resistance and slag resistance, making them a promising alternative to magnesia-chrome refractories in matte smelting furnaces. Herein, we propose a novel approach to enhance both oxidation resistance and slag penetration resistance of such refractories by incorporating Si3N4-Fe powder. The results demonstrated that adding Si3N4-Fe powder effectively enhanced their overall performance. The oxidation resistance of the specimen with 6 wt% Si3N4-Fe was greatly improved because Si3N4 in Si3N4-Fe could promote in-situ reactions to form more forsterite, and the FeO formed by iron oxidation could react with SiC to form Fe-Si alloys; the formed forsterite and Fe-Si alloys worked together to prevent oxygen intrusion. Meanwhile, Si3N4 in Si3N4-Fe promoted the formation of forsterite layer in the corrosion area of refractories, and the reaction of Si3N4 and Fe in Si3N4-Fe formed Fe-Si alloys to prevent slag penetration, which greatly improved the resistance to matte slag penetration of the refractories.