ZnO-CdS nanocomposite material has been synthesized by Chemical Co-precipitation method. The prepared nanocomposite material has been characterized by UV-visible (UV-vis) spectrophotometer and X-ray diffractometer (XRD). The optical band gap of prepared material lies between 3.6 eV to 4.0 eV. The synthesized nanocomposite material has been annealed at two different temperatures 160o C and 200o C. The results of UV-visible characteristic and XRD analysis show that the optical and structural property of the material depends on the temperature at which it has been annealed. A natural dye from beet root extract has been synthesized and has absorbance in visible region. The synthesized nanocomposite material is deposited over the glass plate using spin coater. The thin film of synthesized ZnO-CdS nanocomposite when annealed at higher temperature absorbs more dye than the film annealed at lower temperature. Copyright © 2017 VBRI Press.