Abstract: TiO2 thin films have been prepared firstly by chemical method and then deposited by spin coating technique at 3000 rpm. Films have been annealed at different temperatures (360, 460, 550 and 700°C) for 50 min for each sample. The changes of optical properties with the effect of annealing temperatures such absorption, transmittance and reflectivity have been recorded by UV-Vis spectrophotometer and characterized while the refractive index and energy gap were calculated by Microsoft Excel program. Curves have been adjusted mathematically by using fourth order polynomial correction for smooth curves. Results and behaviors were found that increased absorption, reflectivity and refractive index with increasing of annealing temperature at the wavelengths confined between ∼620-∼800 nm except at 360°C while the transmittance showed a completely opposite behavior of the absorbance and energy gaps decreasing with increasing of annealing temperature.