TiO2 thin films were prepared at various calcinations temperatures by sol-gel process and their structural and optical properties were examined. The influence of calcinations temperature on the structural properties of the prepared TiO2 thin films was investigated by the X-ray diffraction (XRD) and atomic force microscope (AFM). The XRD results showed that TiO2 thin film was transformed into the anatase phase at 350°C, and further into rutile phase at 850°C. The AFM results show quite a smooth surface and are in reasonably well agreement with the crystallite sizes estimated by XRD peak broadening. The influence of calcinations temperature on the optical properties of the prepared TiO2 thin films was investigated by UV-Vis spectrum and variable angle incidence spectroscopic ellipsometer (VASE). The results showed the both anatase phase and rutile phase of the TiO2 thin films prepared have good optical properties in UV region.