Pure GdAlO3: RE (RE = Eu, Pr or Tb) crystalline phase was formed at 900 ℃ with the precursor prepar by nitric-citric combustion process. The synthesis process was studied by XRD, TG-DSC and IR spectra. The analysis results show that there are three main stages in combustion process: ( 1 ) water evaporation and organic compound pyrolysis; (2) combusting reaction; (3)pure crystal formation. GdAlO3: RE powder shows good luminescent properties under 254 nm excitation and was proved to be a good kind of phosphors.