Copper-doped　silica　membranes　were　prepared　via　Sol-Gel　process　with　tetraethylorthosilicate(TEOS)　and　copper　nitrate　as　precursors.　The　status　of　copper　in　the　membranes　was　detected　by　means　of　FT-IR,　XPS,　XRD　and　the　pore　structure　was　determined　by　N(2)　adsorption.　The　effects　of　copper　dopant　and　H(2)O/TEOS　molar　ratio　on　the　pore　structure　were　investigated　and　the　stability　of　the　pore　structure　under　hydrothermal　conditions　was　studied　in　detail.　The　results　show　that　when　the　molar　ratio　of　TEOS　to　H(2)O　is　0.5,　it　leads　to　microporous　structure,　with　a　pore　volume　of　0.155　cm(3)/g　and　a　sharp　pore　size　distribution　centered　at　0.5nm　for　the　sample　with　a　Cu/Si　molar　ratio　of　0.8.　A　faction　of　copper　is　incorporated　into　silica　framework　by　replacing　silicon　atoms,　and　the　residual　mainly　exists　as　crystalline　phase　such　as　Cu　and　Cu(2)O　outside　the　framework.　The　microporous　structure　of　the　doped　samples　could　be　preserved　for　a　short　time　(240h)　under　hydrothermal-conditions　but　finally　collapsed　after　further　hydrothermal　treatment.