A novel Ge-Te-I far infrared transmitting chalcohalide glass system Ge20Te80-xIx(x=2, 4, 6, 8mol%) was prepared by traditional melt-quenching method. Structure and physicochemical properties of Te-based glass system were studied with XRD, SEM and DTA. The effect of halogen on the glass formation and thermal stability was investigated. Optical spectra of Te-based glass system were obtained by spectrophotometer and infrared spectrometer. Effect of halogen on the short-wavelength absorption cut-off edge and infrared transmitting spectra was analyzed. The Tauc equation was used to calculate the direct and indirect optical band gap. The results show that halogen can reduce Te metallic character and improve the glass-forming ability. The density decreased while the molar volume increased with the added I2 content. With the addition of I2, the short-wavelength cut-off edge of the glasses shifts to the longer wavelength (1 700~1 900 nm), the band gap decreased. The thermal stability was enhanced by the addition of halogen. A maximum ΔΤ value of 121℃ was obtained for the glass composition Ge20Te72I8. These prepared Ge-Te-I glasses all have wide optical transmission window from 1.8 to 25 μm, which is a novel far infrared transmitting glass materials.