The selective hydrogenation of benzene to cyclohexene was studied over Ru-Cu/ZnO catalysts, which were prepared by deposition-precipitation, impregnation and co-precipitation methods. The influence of NaOH on the catalytic performance of catalysts prepared by these methods was discussed in detail. It was demonstrated that NaOH significantly enhanced the selectivity to cyclohexene over Ru-Cu/ZnO catalyst prepared by deposition-precipitation method. The properties of the catalysts were characterized by transmission electron spectroscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD). X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption techniques. The effects of ratio of Ru to Cu, concentration of NaOH and other reaction conditions including reaction temperature, hydrogen pressure, and reaction time on the reaction were studied. Using the preferable catalyst, the yield of cyclohexene reached a maximum of 49.4% with benzene conversion of 72.3% and selectivity to cyclohexene of 68.3%. (C) 2011 Elsevier B.V. All rights reserved.