Helicity-dependent　photocurrent　(HDPC)　and　its　modulation　in　topological　insulator　Bi2Te3　nanowires　have　been　investigated.　It　is　revealed　that　when　the　incident　plane　of　a　laser　is　perpendicular　to　the　nanowire,　the　HDPC　is　an　odd　function　of　the　incident　angle,　which　is　mainly　contributed　by　the　circular　photogalvanic　effect　originating　from　the　surface　states　of　Bi2Te3　nanowire.　When　the　incident　plane　of　a　laser　is　parallel　to　the　nanowire,　the　HDPC　is　approximately　an　even　function　of　the　incident　angle,　which　is　due　to　the　circular　photon　drag　effect　coming　from　the　surface　states.　It　is　found　that　the　HDPC　can　be　effectively　tuned　by　the　back　gate　and　the　ionic　liquid　top　gate.　By　analyzing　the　substrate　dependence　of　the　HDPC,　we　find　that　the　HDPC　of　the　Bi2Te3　nanowire　on　the　Si　substrate　is　an　order　of　magnitude　larger　than　that　on　SiO2,　which　may　be　due　to　the　spin　injection　from　the　Si　substrate　to　the　Bi2Te3　nanowire.　In　addition,　by　applying　different　biases,　the　Stokes　parameters　of　a　polarized　light　can　be　extracted　by　arithmetic　operation　of　the　photocurrents　measured　in　the　Bi2Te3　nanowire.　This　work　suggests　that　topological　insulator　Bi2Te3　nanowires　may　provide　a　good　platform　for　opto-spintronic　devices,　especially　in　chirality　and　polarimtry　detection.