Silica　membranes　were　modified　by　fluorocarbon　groups　through　an　acid-catalyzed　co-hydrolysis　and　a　condensation　reaction　of　tetraethyl　orthosilicate　(TEOS)　and　trifluoropropyltriethoxysilane　(TFPTES).　The　cross-sectional　micrograph,　pore　structure　and　hydrophobic　property　of　the　modified　silica　membranes　were　characterized　by　SEM,　nitrogen　adsorption,　FT-IR　and　contact　angle　methods.　The　results　show　that　the　hydrophobic　property　of　the　modified　silica　membranes　has　been　gradually　enhanced,　whereas　the　pore　structure　almost　remains　unchanged　with　the　increase　of　TFPTES　content.　When　the　molar　ratio　of　TFPTES/TEOS　was　increased　to　0.6,　the　modified　silica　membranes　possessed　a　water　contact　angle　of　111.6　degrees　+/-　0.5　degrees　and　a　desirable　microporous　structure,　with　a　pore　volume　of　0.19　cm(3.)g(-1)　and　a　pore　size　of　0.97　nm.　The　hydrogen　transport　in　the　modified　silica　membranes　was　subjected　to　a　micropore　diffusion　mechanism,　with　a　H-2　permeability　of　1.18　x　10(-7)　mol(.)m(-2.)Pa(-1.)s(-1)　and　a　H-2/CO2　separation　factor　of　7.0.