LuBO3:Ln3+ (Ln = Eu, Tb) nanofibers were synthesized via electrospinning combined with heat treatment. The structure analyses show that the as-prepared LuBO3:Ln3+ (Ln = Eu, Tb) nanofibers have porous morphology and average diameters of 200–300 nm, which consist of closely lined nanoparticles with the size of about 30 nm. The fluorescence spectra show that the R/O values are 1.02 and 1.12 for LuBO3:3 mol% Eu3+ nanofibers sintered at 800 and 900 °C, respectively. For LuBO3:xTb3+ (x = 1, 3, and 5 mol%) nanofibers, the emission intensities and the fluorescence lifetime increase slightly with increasing Tb3+ concentration. The fluorescence characteristic of LuBO3:Ln3+ (Ln = Eu, Tb) nanofibers is discussed.