The　circular　photogalvanic　effect　(CPGE)　provides　a　method　utilizing　circularly　polarized　light　to　control　spin　photocurrent　and　will　also　lead　to　novel　opto-spintronic　devices.　The　CPGE　of　three-dimensional　topological　insulator　Bi2Te3　with　different　substrates　and　thicknesses　has　been　systematically　investigated.　It　is　found　that　the　CPGE　current　can　be　dramatically　tuned　by　adopting　different　substrates.　The　CPGE　current　of　the　Bi2Te3　films　on　Si　substrates　are　more　than　two　orders　larger　than　that　on　SrTiO3　substrates　when　illuminated　by　1064　nm　light,　which　can　be　attributed　to　the　modulation　effect　due　to　the　spin　injection　from　Si　substrate　to　Bi2Te3　films,　larger　light　absorption　coefficient,　and　stronger　inequivalence　between　the　top　and　bottom　surface　states　for　Bi2Te3　films　grown　on　Si　substrates.　The　excitation　power　dependence　of　the　CPGE　current　of　Bi2Te3　films　on　Si　substrates　shows　a　saturation　at　high　power　especially　for　thicker　samples,　whereas　that　on　SrTiO3　substrates　almost　linearly　increases　with　excitation　power.　Temperature　dependence　of　the　CPGE　current　of　Bi2Te3　films　on　Si　substrates　first　increases　and　then　decreases　with　decreasing　temperature,　whereas　that　on　SrTiO3　substrates　changes　monotonously　with　temperature.　These　interesting　phenomena　of　the　CPGE　current　of　Bi2Te3　films　on　Si　substrates　are　related　to　the　spin　injection　from　Si　substrates　to　Bi2Te3　films.　Our　work　not　only　intrigues　new　physics　but　also　provides　a　method　to　effectively　manipulate　the　helicity-dependent　photocurrent　via　spin　injection.