A new one-dimensional luminescent composite nanofiber of Eu(TFI)3TPPO/PVP (TFI = 2-(2,2,2-trifluoroethyl)-1-indone, TPPO = triphenylphosphine oxide, PVP = Poly(vinyl pyrrolidone) has been successfully prepared by electrospinning. The unique microstructure, thermal stability, and luminescent characteristics of the composite nanofibers have been revealed by high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), fluorescence microscope (FM), fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), thermogravimetric analysis (TGA), and fluorescence spectrophotometer (FS). The origin of the enhanced luminescent properties of composite nanofibers has been identified by Judd-Ofelt analysis. The experimental results suggest that PVP plays an essential role on the interaction between the Eu(TFI)3TPPO precursor and neighboring chain segments of PVP, leading to the increased polarization degree of Eu3+ ions and significantly enhanced the electronic dipole allowed transitions of Eu3+ ions, which further enhances the luminescent efficiency of composite nanofiber of Eu(TFI)3TPPO/PVP.