Abstract: TiO2 thin films were prepared at low-temperature by the sol-gel method. The as-prepared TiO2 sols were characterized with X-ray diffraction (XRD) and transmission electron microscopy (TEM), TiO2 films were characterized with UV-Vis spectra and atomic force microscopy (AFM), respectively. The photocatalytic activity of the thin films was evaluated by the degradation of rhodamine B in aqueous solution under UV irradiation．The results indicated that a bicrystalline framework of anatase and brookite was present in the as-prepared films. And the TiO2 films showed high transmittance and photocatalytic activity. The effect of sol-refluxing temperature on the performance of TiO2 films was investigated. The increase of sol-refluxing temperature led to the improved photocatalytic activity of TiO2 films. This is due to the crystalline perfection of TiO2 sols and average roughness enlargement of TiO2 films. The TiO2 films prepared by the sol refluxed at 100 ℃ showed the highest photocatalytic activity.