Eu 3? -doped boehmite nanofiber materials with different Eu 3? concentrations were synthesized without any surfactant, and followed by a series of characterizations. It was found that the boehmite nanofibers became coarser with the increase of Eu 3? concentration, which resulted in a gradual decrease of their specific surface areas. Moreover, the thermal stability of the boehmite nanofibers was studied by thermogravimetry-differential scanning calorimetry. All materials showed the phase transition from c-Al 2 O 3 to other forms. Yet the transition temperature was increased with the increase of Eu 3? concentration. The Eu 3? -doped boehmite nanofibers with the maximum Eu 3? concentrations showed the best thermal stability. Photoluminescence spectra showed that the 2 mol% of doping concentration of Eu 3? ions in Eu 3? :-Al 2 O 3 nanofiber was optimum.