The samples of the GeS2- Ga2 S3- CdS pseudo-tary glassy system were prepared by conventional melt-quenching techniques. The microstructure of the GeS2- Ga2 S3 -CdS glasses was analyzed thoroughly using Raman spectra and the relationships among the composition, microstructure and properties ( such as thermal properties, densities , optical properties ) were probed. The experimental results indicate that the GeS2 acts as the network former, the Ga2 S3 as the net intermediate, and the CaS as the net modifier. The GeS2 and Ga2 S3 exist in the form of [ GeS4/2 ], [ GaS4/2 ] tetrahedra or S3 Ge( Ga )- ( Ga ) GeS3 ethane-like units within the glassy network, and the addition of CdS mainly breaks the Ge ( Ga ) - ( Ga ) Ge bonds among the ethane-like units, leading to the formaion of [ GeS4/2 ], [ GaS4/2 ] tetrahedra . The Tg and Tx have tight relations on the congregated degree of glassy network, however, λvis, n and d are hardly involved into the connectional depenmence of the space arrangement.