Abstract: Time-efficient synthesis of resorcinol-formaldehyde/silica composite (RF/SiO₂) aerogels was carried out by using acids as catalysts. RF/SiO₂ aerogels were pyrolyzed to C/SiO₂ aerogels at high temperature. SiC aerogels were successfully converted from C/SiO₂ aerogels by a template-confined magnesiothermic reaction at low temperature (700 ℃). The samples were characterized by XRD, SEM, Raman, FTIR and BET. The results suggest that the products consist of nanocrystalline silicon carbide, and maintain 3D porous network as similar as that of original templates. They possess a bulk density of 130 mg/cm³ and a specific surface area of 230 m²/g. Potentially, the proposed method could be expanded to convert other carbon/metal or semimetal oxide aerogels to carbide aerogels, which could be benefit for investigation of ICF experimental targets.