Nanocrystalline　titanium　dioxide　(TiO2)　particles　coated　with　soy　protein　isolate　(SPI)　were　fabricated　in　aqueous　solution　at　near　room　temperature.　The　X-ray　diffraction,　UV　scanning　spectrum,　photoluminescence　and　FT-IR　measurements　were　applied　to　characterize　the　nanoscaled　composite　structure　of　SPI/TiO2.　Laser　scattering　particle　analyzer　and　zeta　potential　were　used　to　determine　the　average　particle　size　and　stability　of　the　system　in　basic　solutions　by　adding　various　amounts　of　titanium　dioxide.　When　exposed　to　two　hour　irradiation　of　UV　light　at　365　nm,　the　bactericidal　activity　of　SPI　films　containing　TiO2　nanoparticles　(2.00　g/150　mL)　against　Escherichia　coli　and　Staphylococcus　aureus　can　reach　71.01%　and　88.49%,　respectively.　©　2012　Elsevier　B.V.　All　rights　reserved.