Amorphous phosphor 1.4Y2O3·2.5Al2O3·0.1Tb2O3 (the same composition as Y2.8Tb0.2Al5O12) was prepared via a sol-gel method at relatively low temperature (i.c., below 650 ℃), which is much lower than that for the preparation of polycrystalline Y3Al5O12:Tb3+(above 1400 ℃). The amorphous phosphor prepared in the optimized conditions showed a bright green-yellowish luminescence, the intensity of which was comparable with that of polycrystalline sample and the emissions of which were assigned to 5D4→7Fj transitions of Tb3+. Besides the emissions of Tb3+, the amorphous samples prepared at temperatures below 500 ℃ presented a weak blue emission band around 420 nm.