Polycrystalline thin films were prepared from CdO nanoparticles in the chemical Bath deposition (CBD) with different molar concentrations at (0.01, 0.03, 0.05, 0.07) M.
 In order to obtain the best results, the structural and optical properties of CdO films were studied under the influence of increasing molar concentration, the results of the absorbance measurements there showed a change in the absorbance spectrum of the (CdO) films upon the increase in the molar concentration in the deposition, The value of the absorbance is within the limits of short wavelengths and where the absorbance increases at the wavelength (λ≤550 nm), and we note that it increases with the decrease in the wavelength and that the increase in the molar concentration in the deposition leads to an increase in thickness where the greater the absorbance increases the thickness. All samples of the prepared films were examined using scanning electron microscopy (SEM) at 2,000x magnification in order to identify the nature of the surface of the prepared films and to note the change in particle size with increasing molar concentration in the deposition. Experimental results showed that the grain size increases its crystal growth with increasing molar concentration, and this was shown by X-ray, AFM measurements