A　differential　mathematical　model　for　gas　separation　in　hollow　fiber　membrane　and　an　efficient　numerical　solution　procedure　based　on　Orthogonal　collocation　and　Quasi-Newton　method　has　been　developed.　The　procedure　minimized　the　computational　time　and　effort　and　improved　solution　stability　compared　to　other　applied　computational　procedures.　Approximate　analytical　solution　of　the　model　can　be　obtained　which　is　very　useful　in　the　analysis　of　separation　process.　Binary　gas　separation　permeator　for　countercurrent　hollow　fiber　membrane　modules　was　simulated.　Simulation　results　show　good　agreement　with　experimental　results　from　literatures.