Composite　Pt-doped　TiO2　nanotubes　(Pt-TNTs)　were　synthesized　via　alkaline　fusion-hydrothermal　method　(AFHM)　under　ambient　atmosphere　pressure.　Further　systematic　characterization　of　Pt-TNTs　was　performed　by　using　XPS,　surface　photovoltage　spectroscopy　(SPS),　electric　field-induced　surface　photovoltage　spectroscopy　(FISPS),　UV-Vis　diffuse　reflectance　spectrophotometry　(UV-Vis),　TEM,　and　XRD.　XPS　spectrum　showed　double　peaks　which　accounted　for　the　presence　of　platinum　dioxide　and　platinum　oxide　(PtO2　and　PtO,　PtOx　delta+).　Composition　analysis　showed　that　the　particulate　matters　on　surface　of　Pt-TNTs　were　composed　of　PtOx　delta+　and　TiO2.　The　results　of　SPS　and　FISPS　demonstrated　that　the　bound　exciton　showed　sub-band　gap　transition　characteristics　with　the　asymmetric　changes　of　photoelectric　property　corresponding　to　changes　in　polarity　and　strength　of　the　external　electric　field.　Furthermore,　the　influence　of　the　changed　microstructure　morphology　of　Pt-doped　TNTs　on　both　the　photovoltage　spectroscopy　and　the　lifetime　of　photogenerated　carriers　which　occurred　at　the　interfaces　of　Pt-TNTs　was　observed.　Result　of　XRD　indicated　that　a　mixture　of　anatase　and　rutile　phases　prevailed　in　Pt-TNTs.　Contact　potential　barriers　consisting　of　PtOx　delta+,　anatase,　rutile,　and　PtOx　delta+　are　presumed　to　form　upon　PtOx　delta+　particle　that　deposited　on　the　surface　of　Pt-TNTs.