In　the　present　work,　the　surface　hydroxyls　on　rutile　TiO2　that　evacuated　at　different　temperature　were　characterized　by　in　suit　FTIR.　The　action　of　OH　groups　in　photocatalytic　reaction　was　tested　by　adsorption　and　photooxidation　of　toluene　in　an　in　situ　IR　cell.　The　results　show　that　there　are　seven　OH　groups(with　bands　at　3　724,　3　700,　3　652,　3　648,　3　610,　3　413　and　3　362　cm(-1))　on　rutile　TiO2　with　different　thermal　stability.　Among　the　seven　hydroxyl　groups,　the　OH　groups　with　bands　at　3　724,　3　700　and　3　652　cm(-1)　are　thermal　stable　and　are　ascribed　to　isolate　hydroxyl　groups,　while　the　OH　groups　with　bands　at　3　648,　3　610,　3　413　and　3　362　cm(-1)　are　thermal　unstable　that　almost　disappear　after　evacuation　at　250　degrees　C.　During　the　adsorption　of　toluene,　only　the　surface　hydroxyls　with　bands　3　648,　3　610　and　3　652　cm(-1)　act　as　adsorption　sites　for　adsorption　of　toluene.