The sol-gel process has been applied to the preparation of small size CdS crystal doped silica glasses. Silica glasses containing 0.88~30 wt % CdS were synthesized in a process which includes two-step hydrolysis of Si(OC2H5)4 and Cd(CH3COO)2•2H2O,drying and heating of doped gels, and reaction by exposing the porous glass of CdO/SiO2 to H2S gas. The sol-gel transition point was determined by measuring the variation of the viscosity with hydrolysis time. It was found that the gel point was affected by the Cd(CH3COO)2•2H2O content and kinds of acid-catalyst (HNO3 of HCl) . About 2 cm diameter monoliicth dry gel was obtained in the sealed box in which microenvironment (humidity, temperature and chemical atmosphere etc. ) was automatically controlled by the computer. From the results of the low frequency inelastic Raman scattering and transmission electron micrographs, CdS crystals were 1.6 to 8.4 nm in diameter for different doped systems. in the optical absorption spectra, the absorption edge exhibited a blue shift compared with that of the bulk CdS. Thus the quantum size effect was found for glasses containing CdS prepared by the sol-gel process.