Abstract.The possible geometrical structures and relative stability of (SiS2)n (n=16) siliconsulfur clusters are explored by means of density functional theory quantum chemical calculations. The effects of polarization functions and electron correlation are included in these calculations. The electronic structures and vibrational spectra of the most stable geometrical structures of (SiS2)n are analyzed by the same method. As a result, the regularity of the (SiS2)n cluster growth is obtained, and the calculation may used for predicting the formation mechanism of the (SiS2)n cluster.