Abstract: A porous, integral silicon-based composite membrane was developed, with silicon gel and silicon resin as raw materials. Its gas permeability for H₂ is about 10⁵~10⁶ Barrer; and its separation factor for H₂/N₂ is 3~4.13, for O₂/N₂ is 1~1.29. The selectivity of the membrane is improved through surface treatment, upon which the separation factor reaches 16.5 for H₂/N₂ and 5.32 for O₂/N₂. The composite membrane is suitable for hot industral gas separation in an oxidizing environment.