CuO nanowires were prepared by wet-chemical method through the reaction of CuSO4, KOH and ammonia in aqueous solution and subsequent aging process. The XRD, SEM, TEM, HRTEM, CV and galvanostatic method are used to characterize the structure, morphology and electrochemical performance of the as-prepared CuO nanowires. The CuO nanowires are polycrystalline microstructure, which facilitates the electrochemical storing Li. Therefore, the polycrystalline CuO nanowires exhibit a good electrochemical performance as Li ion batteries anode. The CuO nanowires showed a high reversible capacity of 720mAh/g. The capacity keeps up 650mAh/g over 100 cycles.