(100－x)(4GeSe2In2Se3)－xAgI (x=20,30,40 mol%) chalcogenide glasses were prepared by traditional meltquenching method. In this paper, the Xray diffraction(XRD),differential thermal analysis (DTA), visible/nearinfrared absorption spectroscopy, infrared transmission spectra,Raman analysis were adopt to the analysis of the relationships of the composition, structure, thermal stability, and optical properties of the GeSe2In2Se3AgI ternary glass system. The Tauc equation was used to calculate the indirect optical band gap. From the heatingrate dependence of crystallization temperature, the activation energy for crystallization(E) was calculated by the Kissinger equation.The glass samples are amorphous, resulting in a wide composition range of glass formation. A maximum ΔT value of 114℃ and the activation energy for crystallization(Ea=320.4 kJ/mol) were obtained for the glass composition 70(4GeSe2In2Se3) 30AgI. With the addition of AgI, the shortwave absorption of the glasses shifts to the shorter wavelength and the optical band gap increases. In addition, the infrared transmission spectra shows that these prepared glasses all have wide optical transmission and there has been no significant change in infrared cutoff wavelength of the glasses which are all 16 μm or so.