Considering the deposition of TiO2 films on the substrates with lower melting points, anatase TiO2 sol was directly prepared under lower temperature by an improved sol - gel processing and was characterized by XRD, TEM and FT-IR. The effects of process conditions on the crystallinity, crystalline phase and grain size of TiO2 sol, namely, the mol ratio R of n-butyl titanate and water, pH value, aging time and the preparation temperature，were systematically discussed. The results showed that the mol ratio R and aging time had great influence on the crystallinity of TiO2 sol, whereas pH value and the preparation temperature mainly affected its crystalline phases. Besides, more water and lower pH value led to larger grain of TiO2 sol. The flexible TiO2 film electrodes were fabricated on a transparent indium-doped tin oxide coated PET substrate by means of a doctor-blading method using the mixture of the as-prepared TiO2 sol and P25 TiO2 particles. The photoelectrochemical performance of the TiO2 film electrode in Na2SO4 solution was better than that of the commercial TiO2 sol film, whereas its dye adsorbance was slightly smaller than that of the commercial TiO2 sol film because of its somewhat denser structure which could be improved by optimizing the fabrication process.