Abstarct: In this thesis,CdxZn1-xO thin films have been deposited by sol-gel method on to glass and silicon substrates. The prepared samples were annealed at 450℃ and 500℃ for 1 houre. Structural and optical properties of the sample have been investigated. The X-Ray patterns were showed that all of the laxyers, are polycrystalline and have the mix structure of cubic(CdO) and hexagonal(ZnO). The results were deminsterated that the annealing temperature of 500℃ is suitable annealing temprature for the preparation of high qualy Cd_x Zn_(1-x) O thin films.The optical transmittance of the samples, depending on the amount of Cd, that is between %60-%90 in visible wavelength range. Direct and indirect gap of the samples were obtained 3.32eV and 1.56eV, respectively. Effect of Cd concentration for the samples grown on glass and silicon substrates verified that for the samples grown on glass substrate as Cd content increases, the direct gap increases from 2.86eV to 1.97eV, and the indirect gap is decreases from 2.62eV to 1.24eV. The optical transmission of these samples with increasing of cadmium concentration was reduced by about %50. For laxyers grown on silicon substrates, the crystallite size and lattice parameter were increased and decreases, respectively. Comparison of the results were showed that direct band gap of the samples grown on silicon substrates is greater than the samples grown on glass substrates. For samples grown on silicon substrates crystalline size was decreases, but the strain, density and lattice parameters were increased. Dielectrice constants, extinction coefficient and refractive indexces of the samples were calculated.