The refractive index and optical absorption of glass were studied when the BaO was substituted by 0.05, 0.10, 0.15,0.20 (mole fraction) BaF2 respectively in glass 0.20BaO-0.15Ga2O3-0.65GeO2 (mole fraction). The results show that, when fluoride was introduced into glass, the refractive index and dispersion of glass decrease, and the ultraviolet absorption edge shifts to shorter wavelength, but the IR absorption edge doesn't move obviously. The glass without fluoride contains a great deal of OH group that cause optical absorption band at 2.24 μm, 2.97 μm and 4.23 μm. In the glasses containing fluoride, the 2.24 μm absorption band disappears; while the 2.97 μm absorption band and the 4.23 μm absorption band weaken obviously. The origin of every OH absorption band was also discussed and Gaussian separations of the 2.97 μm absorption band of OH group were carried out. The weak peak at about 2.24 μm maybe come from the combination of a stretching mode and two shaking modes of H2O molecular (ν+2ρ); the absorption band at 4.23 μm is caused by the stretching vibrations of the OH groups forming strong hydrogen bond with non-bridge oxygen's (T-OH…O--T); the OH absorption band at about 2.7～3.2 μm can be attributed to the overlapping of stretching bands for the OH groups influenced by various species of hydrogen bond, which causes the asymmetric broadening of absorption band and the shifting of absorption center with OH group content.