The Cu x O (x =1, 2)-embedded carbon nanofibers (Cu x O/CNF) were prepared by electrospinning of the composite solutions of Cu(II) acetate, PAN (polyacrylonitrile) and PVP (polyvinylpyrrolidone), and subsequent stabilization and carbonization. The structure of Cu2O/CNF is largely dependent on the carbonization temperature. The Cu x O/CNF-700 has the disordered CuO structure, while the Cu x O/CNF-800 has the intermediate structure between the disordered CuO and Cu2O. The structural change in the CNF prepared by electrospinning and optimum thermal treatment leads to excellent electrochemical properties. The CNF plays an important role as buffering agent to prevent Cu x O particles from agglomerating. Besides, the aligned CNF with high electrical conductivity leads to the occurrence of Cu nano-particles in the discharging process, and it serves to convert Li2O into Li in the charging process. Both Cu x O/CNF-700 and Cu x O/CNF-800 exhibit high specific discharge capacity, exceptional cycle retention, and excellent reversible capacity even in initial cycle, while Cu x O/CNF-900 shows bad electrochemical performance.