Al3+/Eu2+ co-doped high silica glass is obtained by sintering porous glass impregnated in Al3+ and Eu2+ ion-containing solutions. Effects of different Al3+ concentrations on the fluorescence intensity and the emission peak of Eu2+ ions in high silica glass under ultraviolet (UV) excitation are investigated. The results show that, with the properly increased concentrations of Al3+, a remarkable increase in the flourescence intensity of Eu2+ ions centered at 450 nm under UV excitation can be observed because of both the action of Al3+ ions dispersing Eu2+ ions in the high silica glass matrix and the lower phonon energy of Al2O3. Meanwhile, since Al3+ codopant decreases the splitting extent of 5d energy band of Eu2+ ion in high silica glass, an obvious blue shift of the emission peak of Eu2+ ions can be observed with increasing Al3+ content.