Reaction　of　MCM-41　mesoporous　molecular　sieves　with　tetrabutyl　tin　was　studied　in　a　high　vacuum.　The　composition,　structure　and　properties　of　the　resulted　materials　were　characterized　by　using　element　analysis,　gas　volumetry　analysis,　XRD,　FTIR,　13C　and　119Sn　MAS　NMR,　adsorption　of　nitrogen　and　hydrocarbons　etc.,　respectively.　The　results　showed　that　the　reaction　leads　to　formation　of　multigrafted　species　(≡Si-O)　xSn(n-Bu)4-x　for　MCM-41　dehydrated　at　200°C,　and　to　formation　of　monografted　species　≡Si-OSn(n-Bu)3　for　MCM-41　dehydrated　at　500°C.　Grafting　butyltin　species　onto　the　surface　resulted　in　reduction　of　MCM-41　pore　size　and　modification　of　adsorptive　performance　of　MCM-41　to　hydrocarbons.