In this work, CuO thin films were prepared by spray pyrolysis method using different concentration of CuCl2 .2H2O. X- ray diffraction (XRD) and UV-VIS transmission spectroscopy were employed to characterize the structure and optical properties of prepared films.XRD patterns show that the films are polycrystalline and monoclinic with (-111) and (111) crystalline orientations. The optical band gaps (2.05 to2.42eV) ,with high absorption coefficient change from (3*105 - 1*105) cm-1 at 0.3M concentration , and excitation coefficient change from (0.85 – 0.7). These constants are found to be oscillatory in nature, which are attributed to the particular structure of films and their concentration.