Abstract: CdZnSe2xTe2(1-x) thin films for different composition parameters ‘x’ have been deposited on large substrate area by the spray pyrolysis method which is simple, inexpensive and economical at 300o substrate temperature. From the optical transmission and reflection spectra, absorption coefficients were calculated . Band gap energy were determined from absorbance measurements in visible range using Tauc theory. Band gap energy values are found to lie in the range 2.04-2.52 eV for the films with composition parameter, x= 0 to 1. It shows that the main transition at the fundamental absorption edge is a direct allowed transition. The optical constants such as optical band gap, extinction coefficient, refractive index and dielectric constant have been calculated for these films The values obtained by this method are suitable for many scientific studies and technical applications such as solar cells, heat mirrors , transparent electrodes, piezoelectric devices, sensors etc.