Anatase TiO2 thin films were successfully prepared on glass slide substrates via a sol-gel method from refluxed sol (RS) containing anatase TiO2 crystals at low temperature of 100 T. The influences of various refluxing time on crystallinity, morphology and size of the RS sol and dried TiO2 films particles were discussed. These samples were characterized by infrared absorption spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission-scanning electron microscopy (FE-SEM) and UV-vis absorption spectroscopy (UV-vis). The photocatalytic activities of the TiO2 thin films were assessed by the degradation of methyl orange in aqueous solution. The results indicated that titania films thus obtained were transparent and their maximal light transmittance exceeded 80% under visible light region. The TiO2 thin films prepared from RS-6 sol showed the highest photocatalytic activity, when the calcination temperature is higher than 300 degrees C. The degradation of methyl orange of RS-6 thin films reached 99% after irradiated for 120 min, the results suggested that the TiO2 thin films prepared from RS sol exhibited high photoactivities. (c) 2006 Elsevier Ltd. All rights reserved.