Mesoporous　organic-inorganic　hybrid　silica　with　ethylidene　bridging　group　between　two　silicon　atoms　was　prepared　via　a　sol-gel　and　hydrothermal　synthesis　process　by　using　silsesquioxane　(1,2-bis(triethoxysilyl)　ethane,　BTESE)　as　silicon　source　and　triblock　copolymer　poly(ethylene　glycol)-b-poly(propylene　glycol)-b-poly(ethylene　glycol)　(P123)　in　combination　with　dodecyltrimethylammonium　bromide　(DTAB)　as　template.　Factors　that　affect　the　morphology　and　pore　structure　of　silica　particles　were　investigated　in　detail　by　means　of　scanning　electron　microscopy,　transmission　electron　microscopy　and　nitrogen　adsorption-desorption.　The　results　show　that　the　sphericity　and　surface　smoothness　of　organic-inorganic　hybrid　silica　are　distinctly　enhanced　with　increasing　amount　of　DTAB　and　hydrochloric　acid.　Meanwhile,　suitable　synthesis　time　and　crystallization　temperature　are　beneficial　to　the　formation　of　silica　spheres　with　improved　sphericity.　The　organic-inorganic　hybrid　silica　spheres　prepared　with　a　DTAB/BTESE　molar　ratio　of　0.8,　a　HCl/BTESE　molar　ratio　of　6,　an　aging　time　of　24　h　and　a　crystallization　temperature　of　100　A　degrees　C　exhibit　a　particle　size　of　around　1.7　A　mu　m,　a　high　surface　area　of　1063.35　m(2)　g(-1)　and　a　narrow　pore　size　distribution　centered　at　3.12　nm.