Topological　insulators　(TIs)　are　considered　as　ideal　spintronic　materials　due　to　the　spin-momentum-locked　Dirac　surface　states.　The　photoinduced　anomalous　Hall　effect　(PAHE)　is　a　powerful　tool　to　investigate　the　spin　Hall　effect　of　topological　insulators　even　at　room　temperature.　In　this　Letter,　the　PAHE　has　been　observed　in　three　dimensional　topological　insulator　Bi2Te3　thin　films　grown　on　Si　substrates　at　room　temperature.　As　the　thickness　of　the　Bi2Te3　films　increases　from　3　to　20　quintuple　layer　(QL),　the　PAHE　first　increases　and　then　decreases,　and　it　reaches　a　maximum　at　7　QL.　The　sign　reversal　of　the　PAHE　of　the　3　QL　sample　after　oxidation　reveals　that　the　PAHE　of　the　Bi2Te3　thin　films　is　dominated　by　the　top　surface　states,　which　is　further　confirmed　by　the　circular　photogalvanic　effect　under　front　and　back　illuminations.　The　photoinduced　anomalous　Hall　conductivity　excited　by　1064nm　light　is　as　large　as　5.28nA　V-1　W-1　cm(2)　in　the　7　QL　sample,　much　larger　than　that　observed　in　InGaAs/AlGaAs　quantum　wells　(0.445nA　V-1　W-1　cm(2))　and　GaN/AlGaN　heterostructures　(0.143nA　V-1　W-1　cm(2)).　By　comparing　the　PAHE　current　excited　by　1064nm　with　that　excited　by　1342nm,　we　reveal　that　the　tremendous　PAHE　excited　by　1064nm　light　is　due　to　the　modulation　effect　of　spin　injection　from　Si　substrates.　The　giant　PAHE　value　observed　in　TI　Bi2Te3　may　offer　spintronic　applications　of　TIs　such　as　high-efficient　light-polarization-state　detectors.