The optical constants of thin film prepared by cadmium hydroxide nanoparticles spray coated on the glass substrate held about at 100 °C temperature have been investigated using the optical transmission and reflection spectra. The transmission spectrum exhibits that the film has a high transparency (~80%) at the infrared region. From standard optical analysis, direct band gap energy of Cd(OH)2 was found as 3.13 eV, and also, it was seen that the calculated refractive index varies between 1.65 and 2.15 throughout the spectral region considered. The dispersion parameters such as oscillator energy, dispersion energy, and static and high frequency refractive index were determined in regard to the Wemple DiDomenico single oscillator model. Finally, some dielectric parameters of material such as relaxation time, dissipation (loss) factor, volume and surface energy loss functions and optical conductivity were calculated