Cadmium sulphide (CdS) thin films have been deposited by chemical bath deposition method (CBD) on CdTe substrates. The temperature of the deposition was varied from 40 oC to 70oC under stirring, pH of complexing agent about 10-11.5 and doping by CdCl2. The morphology was composed of small columnar crystals, characterized by SEM. The crystallographic structure contains a mixture of hexagonal and cubic structures were study by TEM. The energy gap values 2.395 eV were found calculated by reflectance spectra using UV-VIS spectrometer. This study showed the correlation of deposition temperature, grain size, energy gap and observed some properties of CdS nanocrystal in the films.