Silicon carbide (SiC) is one of the promising materials for high-temperature hydrogen separation membranes because of its thermal and chemical stability. It has already been suggested that the pore structure and gas permeation performance of precursor-derived SiC-based inorganic membranes can be tailored by optimization of various factors encountered during and pre/post pyrolysis steps. It was found in this study that addition of polystyrene, appropriate oxidation of the membrane, and low-temperature thermal cross-linking contribute to improved gas permeation performance (H-2 permeance and H-2/N-2 permselectivity).