Titanium dioxide (TiO 2 ) thin film prepared in a simple chemical method, on an optically flat a glass substrate. The effect of the annealing temperature on a structural and the optical properties of TiO 2 films is studied systematically by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), UV-VIS spectroscopy . The XRD patterns show that the deposited films and the annealed films are polycrystalline and the average grain size of the crystallite grains ranges from 41 to 50 nm in films. AFM images reveal a regular grain distribution of grains in films and the grains in the nanoscale dimension. The UV-Vis rays results show that increase in transmittance with increase the annealing temperature, also ,the energy gap decreases from 3.6 to 2.6 volts, due to the effect of quantum volume.