Influence of coexisting Al2O3 on the catalytic activity for low-temperature water-gas-shift (LT-WGS) reaction over Cu catalyst was investigated. The catalytic activity of Cu/Al2O3 catalyst increased with decreasing mesopore size when S/C ratio was 2.2, whereas the catalytic activity with S/C ratio = 4.6 increased with increasing mesopore size. IR measurement combined with kinetic study suggested that the low catalytic activity of Cu/CeO2 catalyst comes from the restriction of CO adsorption on Cu-0 by bidentate-type carbonate formed on the strong basic site of CeO2 support. On the other hand, it was found that bidentate-type carbonate was not formed on Cu/Al2O3 showing high catalytic activity for LT-WGS reaction. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.