We have developed a simple synthetic method to prepare the hybrid microspheres of CdS nanoparticles on the surface of silica microspheres modified by (3-mercaptopropyl) trimethoxysilane (MPS). The -SH groups of MPS can bind with the Cd2+ ions on the surface of SiO2. When thioacetamide releases H2S, the nanosized CdS particles (1-6 nm) will successfully be generated on the silica surface under the experimental conditions. The size of the CdS nanoparticles was found to be related to the concentration of Cd2+ feed and the size of silica spheres, the higher the concentration of Cd2+ and the larger of silica microspheres, the bigger the size of CdS nanoparticles. Techniques including UV, PL, TEM and XPS were used to characterize the CdS-SiO2 hybrid microspheres.