In this study, optical properties of thin films made of different volume ratios of polysulfone (PS) and magnesium oxide (MgO) thin film deposited on germania (GeO2 ) were studied as a function of wavelength in the range 0.3 – 1.1 μm using Matlab. Refractive indices, extinction coefficients, and absorption coefficients were investigated. The transmittance spectra of the PS-MgO thin films of different thicknesses deposited on the GeO2 substrate were also examined. The films were found to show an increase in transmittance with an increase in the MgO percentage the thin film. However, the absorbance of the film was found to be high in the ultraviolet. The results give good reason for the applications of MgO thin films in optoelectronic devices.