Abstract: Zn nanowires were fabricated by directelectro-deposition with porous aluminum oxide membrane as the templates, and ZnO nanowire arrays were prepared via the high temperature oxidation of Zn nanowires. The aperture of alumina template was altered by changing the process parameters of the preparation of alumina membranes. Therefore, the diameter of ZnO nanowires was changed, too. X-ray diffraction, transmission electron microscope were employed to study the morphology and chemical composition of ZnO nanowires. It was found that the diffraction peaks increase with the diameters of ZnO nanowires increasing. The photoluminescence property of the sample was measured with an FLS920 spectrofluorimeter, and the effects of the morphologies of ZnO nanowires on the photoluminescence were analysed by gauss curve fitting method. The results indicate that the crystallinity and the stoichiometric proportion improve gradually with the diameters of nanowires increasing from 30 nm to 60 nm. The emission peaks of ZnO nanowires with diameters of 30 nm, 40 nm, 45 nm and 55 nm in the region of ultraviolet and blue band showed a blue shift with the diameters of nanowires increasing, however, the peaks of ZnO nanowires with a diameter of 60 nm exhibited an opposite tendency. It can be deduced that there is a critical value of diameter that makes the photoluminescence property of ZnO nanowires different.