In this paper, effects of potential and output mode on copper nanowire arrays via porous anodic aluminum oxide template by electrochemical deposition method have been investigated. The copper nanowire arrays were fabricated using electrochemical deposition in 0.2 M CuSO4 by different potential modes including direct current (DC) and pulse. The nanostructure, morphology, chemical composition and phase of copper nanowire arrays were examined by scanning electron microscopy and grazing incidence X-ray diffraction. The results indicated that the copper nanowire arrays deposited by pulse mode revealed high aspect ratio despite high potential while that at higher DC potential was rather short due to the hydrogen generation in reduction reaction. The short duty cycle of 50% in pulse deposition can release the produced hydrogen for good nanowires formation.