Copper oxide nanowires with an average length of 7.4μm are prepared by in-situ thermal oxidation at 500°C for 6h in air, and their lithium storage performances are promoted by a further ammonia treatment. The morphologies, structures and lithium storage properties of copper oxide nanowire arrays are investigated by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and a series of electrochemical measurements. The results show that after the reprocessing, the CuO nanowire arrays exhibit a higher reversible capacity of 645 mAhg−1 after 100 cycles at a current density of 50 mAg−1, excellent cyclability and high-rate capability. The good electrochemical performance and simple preparation process make it a promising anode material for lithium-ion batteries.