Si3N4 porous ceramics were fabricated by a combined foam-gelcasting and catalytic nitridation method at 1 473-1 623 K using silicon powder as the starting material, hexadecyl trimethyl ammonium bromide (CTAB) as the foaming agent, and different amounts of micron Fe powder as the catalyst. The effects of the nitridation temperature and the Fe powder addition on the phase composition, the mechanical properties, and the microstructure of the samples were researched. The results show that when nitriding at 1 573 K for 5 h and adding 1 mass% Fe powder (with respect to the Si powder), the sample has a high porosity and suitable mechanical properties: the porosity of 76.5%, the compressive strength of 16.2 MPa, and the specific strength of 22.7 MPa · cm³ · g^-1.