The pure hexagonal phase YBO3:Tb3+ phosphors with good crystallinity and uniform size were prepared by hydrothermal reaction (HR). The particle size and morphology can be well controlled by adjusting the concentration of ammonium acetate and varying the reaction temperature and time. The phosphor prepared by FIR emits an intense green light at 543 nm, which is stronger than that from crystals synthesized by solid-state reaction (SR). The influence of Tb3+-doping concentration on the crystallization and luminescent properties were investigated. The results showed that the samples exhibited a higher quenching concentration of Tb3+ in comparison with those prepared by the SR. The phenomena were also discussed. (c) 2005 Elsevier B.V. All rights reserved.