The　surface　of　NiTi　alloy　was　roughened　by　NaOH-HCl　treatment,　and　the　Ta-containing　TiO2　films　were　coated　on　the　pretreated　NiTi　alloy　by　the　sol-gel　method.　Thermal　analyses　indicate　that　the　evaporation　temperature　of　the　organics　decreases　with　the　addition　of　tantalum　ethoxide　in　the　TiO2　sol,　but　the　crystallization　temperature　of　anatase　increases.　The　NaOH-HCl　pretreatment　improves　the　film　integrity,　but　cracks　still　form　in　the　films　at　high　Ta　contents　(a　parts　per　thousand　yen20　%,　molar　ratio)　owing　to　the　increasing　film　thickness.　X-ray　diffraction　(XRD)　confirms　that　the　addition　of　Ta　suppresses　the　crystallization　of　anatase.　X-ray　photoelectron　spectroscopy　(XPS)　reveals　that　Ta　exists　as　Ta2O5　in　the　film.　With　the　increase　of　Ta　content,　the　hydrophilic　conversion　of　the　films　under　UV　illumination　is　impeded,　but　their　corrosion　resistance　in　0.9　%　NaCl　solution　increases,　tested　by　the　potentiodynamic　polarization.　The　coating　samples　have　acceptable　hemolysis　ratios　for　biomaterials　(＜　5).　The　introduction　of　Ta　improves　the　anti-aggregating　function　of　the　TiO2　film　in　the　platelet　adhesion　test.