A new phosphor of the K 2 [Al(B 5 O 10 )]:Eu 3+ was prepared by annealing of the as-prepared of the precursor of K 2 [Al(B 5 O 10 )]Á4H 2 O:Eu 3+ at 300-400 C, and which has been synthesized under facile hydrothermal conditions. All the samples were characterized by the EDS, XRD, FT-IR, and SEM. A systematic study on their luminescent properties has been performed by the PL and PLE. A series of influencing factors on the luminescent properties were also investigated. The PL and PLE studies reveal that the phosphor of K 2 [Al(B 5 O 10 )]:Eu 3+ with optimal luminescent intensity and higher red-orange ratio were obtained by sintering the precursor at 400 C for 5.5 h, with 9% doping concentration, which suggests that it might as a potential application of the light display systems.