The CdS thin films were prepared on ITO, FTO and AZO substrates by RF magnetron sputtering technique and chemical bath deposition technique. The morphology, structure and optical properties of all samples were characterized by the scanning electron microscopy, X-ray diffraction and ultraviolet-visible spectroscopy. The results show that the microstructure of CdS thin films dependent on the type of substrate by different deposition techniques, the grain size is larger by chemical bath deposition technique, but the surface are relatively rough. All the prepared CdS thin films show a mixed phase structure of cubic and hexagonal. The diffraction peaks by sputtering is clear, sharp, and the crystalline is better than chemical bath deposition technique. The optical transmittance of CdS thin film by chemical bath deposition technique is inferior to those of CdS films by sputtering, but the advantage in the short wave direction is clearly.