Using low temperature synthesized BCNO phosphors as raw materials, monodispersed BCNO nanoparticles (similar to 10 nm) are obtained successfully after a two-step centrifugation. X-ray diffraction results indicate that these BCNO nanoparticles are mainly hexagonal BN phase. These BCNO nanoparticle-embedded polymer nanofibers with an average diameter of 300 nm are prepared by electrospinning. Photoluminescence spectra of these nanofibers indicate that the emission can be readily tuned by adjusting the C concentration in the BCNO phosphors. These nontoxic nanofibers with intense tunable emission may find potential applications in the fields of lighting, biological marker, optoelectronic nanodevices, etc.