In this study, a series of ZnO-Al2O3 catalysts with various ZnO/(ZnO + Al2O3) molar ratios have been evaluated for the high-temperature steam reforming of methanol, and the optimizing catalyst composition consists in the range of 0.50-0.67. The catalysts were characterized by N-2 adsorption-desorption, X-ray diffraction and UV-vis spectra. In the case of ZnO/(ZnO + Al2O3)> 0.5, a significant proportion of Zn could dissolve in ZnAl2O4, resulting in Zn-rich non-stoichiometric spine!, in which the Zn2+ ions located both at the tetrahedral and octahedral sites. It was noticed that such a coordination of Zn2+ ions in the octahedral position brought about a higher CO selectivity. Further investigation illuminated water gas shift and methanol decomposition reaction were both involved in the formation of CO. There was no noticeable deactivation for ZnO-Al2O3 with the ZnO/(ZnO+ Al2O3) molar ratio of 0.50 during the 200h continuous operation (GHSV= 17930 h(-1), T=420 degrees C). The H-2 space time yield is 55 Lh(-1)g(cat)(-1) and the concentration of CO in the dry gaseous products was lower than 0.8%. (C) 2010 Elsevier B.V. All rights reserved.