Eu-doped oxyfluoride aluminosilicate glasses were prepared by melt-quenching method. The glass samples were characterized by photoluminescence (PL) spectroscopy and electron paramagnetic resonance techniques. In the glass samples, the reduction of Eu3+ to Eu2+ ions occurred in the air condition. The PL spectra showed that the intensity of 4f65d -> 4f7 transition of Eu2+ ions increased and the corresponding peak wavelength decreased with increasing fluorine anion concentration. Meanwhile, the relative emission intensity ratio of Eu2+ to Eu3+ also depended on the content of fluorine anions. A possible reduction mechanism was discussed.