The　nanoscale　TiO2　thin　films　have　been　successfully　fabricated　by　liquid　phase　deposition　(LPD)　method.　The　microstructure,　morphology,　and　phase　composition　were　investigated　through　Scanning　Electronic　Microscopy　(SEM)　and　X-ray　Diffraction　Patterns　(XRD)　method.　The　photoelectronchemical　properties,　such　as　polarization　curves,　variations　of　open-circuit　potential　function　with　time　in　presence　and　absence　of　simulated　solar　light　(metal　halogen　lamp)　were　studied.　The　experimental　results　showed　that　anatase　could　be　obtained　after　the　deposited　thin　films　being　annealed　at　500　°C.　The　corrosion　potential　of　the　thin　film　shifted　from　100　mV　to　-114　mV　under　illumination　of　simulated　solar　light.　The　changes　of　the　open-circuit　potential　of　the　thin　films　decreased　under　illumination　and　increased　in　the　dark.　The　mechanism　of　the　cathodic　protection　of　TiO2　nanoscale　thin　films　for　304　stainless　steel　was　studied　in　this　paper.