TiO2　photocatalyst　was　prepared　by　sol-gel　method,　and　then　loaded　with　1.0wt.%　Pt　by　impregnation-chemical　reduction　method　(denoted　as　PT).　Photocatalytic　reforming　(PR)　of　C3-polyols　(glycerol,　propyleneglycol,　and　isopropanol)　which　have　similar　carbohydrate　structure　but　possess　different　number　of　OH　groups　for　H2　production　over　PT　was　performed　to　study　the　role　of　their　OH　groups　in　the　reforming　reaction.　The　results　indicated　that　the　H2　evolution　rate　and　the　mineralization　efficiency　of　polyols　(oxidized　to　CO2)　are　highly　correlated　with　the　number　of　OH　groups　they　contain.　The　more　OH　group　it　has,　the　higher　H2　evolution　rate　can　be　obtained,　as　well　as　the　generation　of　CO2.　The　roles　of　the　OH　group　were　discussed　in　terms　of　providing　an　anchor　for　the　chemical　adsorption　of　polyols　to　the　PT　and　serving　as　an　effective　holes　scavenger　to　trigger　the　reforming　reaction.　For　a　polyol　molecule,　only　OH　directly　connected　segment　can　be　effectively　converted　to　H2　and　CO2　via　the　PR　process.　©　2011　Elsevier　B.V.