Eu(BA)3Phen ternary complexes by benzoic acid and 1,10-Phenanthroline were synthesized and the fluorescent nanofibers with polyacrylonitrile polymer were prepared by electrostatic spinning technology. Scanning electron microscope, fluorescence and absolute spectra were used to study its microstructure and fluorescence characteristics, respectively. The results claim that Eu(BA)3Phen complex doped polyacrylonitrile fibers are randomly arranged with uniform diameter ~ 200 nm. Under ultraviolet-B radiation, the nanofiber emits lightful red fluorescence. With the content of europium complex increased, the emission intensity of nanofibers is significantly enhanced due to the effectiveness of energy transfer. Under the excitation of 308 nm light emitting diode with 115.61 mW pumping power, the total emission photons are derived to be 25.71×1011, 61.50×1011 and 106.12×1011 cps, corresponding to 1 wt%, 2 wt% and 4 wt% Eu(BA)3Phen doped polyacrylonitrile nanofibers, respectively. Among them, the number of emitting photons by the 5D0→7F2 transition of Eu3+ reaches 15.98×1011, 41.21×1011 and 70.76×1011 cps, respectively. The maximum stimulated emission cross-sections of Eu3+ from 5D0→7F2 is calculated to be 4.12×10－21 cm2, showing the strong light radiation ability of nano-fluorescent fibers. Fluorescence quantification reveals the high photon-conversion efficiency of Eu(BA)3Phen doped polyacrylonitrile nanofibers and provides the broader application prospects in the field of sensitization of flexible solar cells as a ultraviolet-visible conversion layer.