The blue phosphor BaMgAl10O17:Eu2+ particles with sphericity and nonaggregation was prepared by high-temperature spray pyrolysis. Characteristics of the as-prepared and the post-treated particles such as crystallinity, morphology, and luminescence were investigated. The as-prepared particles at 1200 degrees C had an amorphous phase, and the sphericity of as-prepared particles disappeared after post-treatment at 1300 degrees C. On the other hand, the as-prepared particles at 1500 and 1700 degrees C have good crystallinity of BaMgAl10O17, and its morphology was maintained after post-treatment. The mean size of particles obtained from 0.3 M solution was 0.6 mu m. The particles which were directly prepared by spray pyrolysis had higher PL intensities than these of post-treated particles. The good morphology of particles directly prepared by spray pyrolysis caused the high luminescence intensity in comparison with the post-treated particles.