Novel one-dimensional polyvinylpyrrolidone (PVP)/[Sr(NO3)2 + Mg(NO3)2 + TEOS + Eu(NO3)2 + Dy(NO3)2] composite fibers were prepared via electrospinning, and then it was calcined at high temperature to fabricate the long-persistent luminescence Sr2MgSi2O7:Eu2+, Dy3+ nanofiber by solid-state reaction under a reducing atmosphere. X-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy and fluorescence spectrophotometer as well as afterglow brightness tester were used to characterize the resulting samples. The results revealed that diameter of the composite nanofibers decreased firstly and then increased with the increasing of the calcination temperature. FTIR analysis manifested that there was two new absorption peaks around 660 and 834 cm−1, which corresponded to Mg–O stretching and Sr–O stretching, when PVP/[Sr(NO3)2 + Mg(NO3)2 + TEOS + Eu(NO3)2 + Dy(NO3)2] composite nanofibers was calcined at the temperature of 1,100 °C, indicating that the crystalline Sr2MgSi2O7:Eu2+, Dy3+ had formed. Furthermore, its luminescence properties were tested. Upon excitation in the UV region, the emission spectra consisted of broad emission band, and the emission peak was located at the wavelength of 468 nm. Decay process contained both rapid-decaying and the slow-decaying processes, which due to the short survival time of the electro in Eu2+ and the deep trap energy center of Dy3+.