Zinc sulfide thin films have been deposited onto glass substrates by chemical bath deposition. Thin films of ZnS with different thicknesses of 720nm to 1045 nm were calculated from UV parameters. The effect of film thickness on structural and electrical properties was studied. The thermal conductivity of ZnS thin film is 0.88W/K-m. The structural and activation energy studies support this decrease in the resistivity due to improvement in crystallinity of the films which would increase the charge carrier mobility and decrease in defect levels with increase in the thickness of film. Aim of the work is analyzed the particle structure by X-ray Diffraction (XRD), surface morphology Scanning Electron Microscopy (SEM) and optical properties by UV-Visible spectroscopy and thermal conductivity ZnS thin films. The result indicates that the conductivity of the buffer layer is generated the carriers with minimal losses while coupling light to the junction with minimum absorption losses, yields a highly efficient solar cell.