La2O2CN2:Er(3+)andLa(2)O(2)CN(2):Er3+/Yb(3+)upconversion (UC) luminescence nanofibers were successfully fabricated via cyanamidation of the respective relevant La2O3:Er3+ and La2O3:Er3+/Yb3+ nanofibers which were obtained by calcining the electrospun composite nanofibers. The morphologies, structures, and properties of the nanofibers are investigated. The mean diameters of La2O2CN2:Er3+ and La2O2CN2:Er3+/Yb3+ nanofibers are 179.46 +/- 12.58nm and 198.85 +/- 17.07nm, respectively. It is found that intense green and weak red emissions around 524, 542, and 658nm corresponding to the (H11/2I15/2)-H-2-I-4, (S3/2I15/2)-S-4-I-4, and (F9/2Il5/2)-F-4-I-4 energy levels transitions of Er3+ ions are observed for La2O2CN2:Er3+ and La2O2CN2:Er3+/Yb3+ nanofibers under the excitation of a 980-nm diode laser. Moreover, the emitting colors of La2O2CN2:Er3+ and La2O2CN2:Er3+/Yb3+ nanofibers are all located in the green region. The upconversion luminescent mechanism and formation mechanism of the nanofibers are also proposed.