The　grafting　of　tetraneopentyl-titanium　onto　the　surface　of　MCM-41　mesoporous　molecular　sieves　prior　to　pretreatment　at　500　degreesC　under　10(-2)　Pa　vacuum　generated　a　well-defined　bigrafted　surface　complex　(equivalent　to　Si　-　O)(2)Ti((CH2CMe3)(2).　The　Si　-　O)(2)Ti(CH2CMe3)(2)　readily　reacts　with　CH3OH,　H2O　and　O-2　to　produce　(equivalent　to　Si　-　O)(2)Ti(OCH3)(2),　(　equivalent　to　Si　-　O)(2)Ti(OH)(2)　and　(　equivalent　to　Si　-　O)(2)Ti(OCH2CMe3)(2)　at　room　temperature,　respectively.　Further　calcination　in　oxygen　at　500　degreesC　of　the　hydrolyzed　products,　(　equivalent　to　Si　-　O)(2)Ti(OH)(2),　resulted　in　surface　titanium　oxides.　All　the　above　reactions　were　followed　by　in　situ　FTIR　and　the　resulted　products　were　characterized　by　elemental　analysis,　XRD,　nitrogen　adsorption,　FTIR　and　DRS.　It　is　showed　that　the　grafting　reaction　and　post-treatments　did　not　affect　the　characteristic　structure　of　MCM-41.　The　surface　area　and　pore　diameter　of　the　Ti-MCM-41　are　slightly　less　than　that　of　MCM-41.　The　Ti　atoms　are　tetrahedrally　coordinated　on　the　surface　of　MCM-41.　Catalytic　test　revealed　that　the　Ti-MCM-41　has　evident　photocatalytic　activity　toward　ethylene.　The　reason　for　photocatalytic　activity　of　the　molecular　sieve　was　discussed　by　comparing　for　the　structure　and　properties　of　Ti-MCM-41　with　that　of　[Ti]-MCM-41.