Trifluoropropyl-modified　silica　membranes　were　prepared　by　sol-gel　technique　using　tetraethyl　orthosilicate　(TEOS)　and　(trifluoropropyl)trimethoxysilane　(TFPTMS)　as　precursors.　The　effect　of　trifluoropropyl　modification　on　the　hydrophobic　pore　structure,　properties,　hydrogen　permeation　and　separation　properties　and　long-teiiii　hydrothermal　stability　of　the　modified　silica　membranes　were　investigated　in　detail.　The　results　show　that　the　modified　membranes　retain　a　desirable　microporous　structure　with　a　pore　size　distributed　from　0.45　to　0.7　nm.　The　hydrophobic　property　of　silica　membranes　has　been　considerably　enhanced　after　modification,　with　a　water　contact　angle　of　(102.7　degrees　+/-　0.1　degrees)　at　a　TFPTMS/TEOS　molar　ratio　of　0.6.　The　hydrogen　transport　in　the　modified　silica　membranes　complies　with　a　micropore　diffusion　mechanism,　with　a　single　H-2　permeance　of　4.77x　10(-7)　mol.m(-2).s(-1).Pa-1,　a　H-2/CO2　permselectivity　of　6.99　and　a　H-2/CO2　binary　gas　mixture　separation　factor　of　6.93　at　300　degrees　C,　higher　than　Knudsen　permselectivity　(4.69).　Under　a　humid　condition　with　a　temperature　of　200　degrees　C　and　a　water　vapor　molar　ratio　of　5%,　the　single　H-2　permeance　slightly　decrease　in　the　first　3　hours　and　then　almost　remain　constant　for　at　least　220　hours,　indicating　that　the　modified　membranes　are　more　hydrothermally　stable　than　pure　SiO2　membranes.