In this paper we report the observation of coupled phonon modes of CdS spherical quantum dots (QDs) embedded in porous Al2O3 (por-Al2O3) matrix. We have used thermodynamical calculations to develop a technique of CdS QDs deposition in porous anodic alumina. Optical phonons confined in nearly spherical CdS QDs have been studied, both theoretically and experimentally. Spatially quantized phonon modes are considered in the framework of a continuum model. Raman scattering and absorption of far-infrared radiation in CdS QDs have been studied.