A new series of chalcohalide glasses in the GeS2–In2S3–CsI pseudo-ternary system were prepared by conventional melt-quenching method. The glass-forming region was determined and it is mainly situated in the GeS2-rich domain. The glasses have relatively high glass transition temperatures (Tg ranges from 335 to 405 �C) and good thermal stabilities. Based on the Raman spectra, it can be speculated that the glassy net is mainly constituted by [GeS4] and [InS4�xIx] tetrahedra, which are interconnected by the bridging sulfur atoms. And the ethane-liked structural units [S3Ge–GeS3] can be formed because of the lacking of sulfur. Cs+ ion, which was added from CsI, exists as the nearest neighbor of I� ion.