The homogeneous G eS2-In2 S3-Csl glassy samples were prepared by conventional melt-quenching method.When the molar ratio of In2 S3 to CsI remains 1, the non-crystalline region can extend to the composition 0.4 GeS2 - 0.3 In2 S3 - 0.3 CsI.And with the addition of CsI, the glass-forming ability of this serial glass reaches its maximum at the composition 0.8 GeS2 - 0.1 In2 S3 - 0.1 CsI.According to the Raman spectra, the microstructure of these glasses is mainly constituted by [ GeS4 ] and [ InS4-xIx]tetrahedra, which are interconnected by the bridging sulfur atoms; meanwhile, the ethane- liked structural units [ S3 Ge- GeS3 ] can be formed because of the lacking of sulfur; Cs+ ion, which is ndded from CsI, exists as the nearest neighbor of I-ion in the glassy network.