Highly luminescent hybrid CdS (diameter ¼ 3-6 nm)/copolymer nanocomposites are prepared by using the soap-free emulsion polymerization with chemical precipitation methods in this investigation. The core/shell type of ZnS/CdS nanoparticle on the shell layer of the copolymer microsphere can be obtained via the ion-exchange method. The luminescent intensity and energy of the hybrid CdS/copolymer nanocomposite not only can be improved by increasing the pH value due to the surface passivated by the iminodiacetic acid sodium salt of the polymer side chain, but also can be enhanced by the higher band gap inorganic materials ZnS shell layer. In addition, the CdS nanoparticle passivated by inorganic shell ZnS is more robust than when organically passivation. Furthermore, these hybrid nanoparticles are easily employed to manufacture the transparent copolymer membrane at the film formation temperature (608C), and they still keep their high luminescent property.