A　series　of　aluminum　promoted　Cu/CeO2　nanocatalysts　with　aluminum　content　in　the　range　of　0-5wt.%　were　prepared　by　co-precipitation　method　and　examined　with　respect　to　their　catalytic　performance　for　the　water-gas　shift　(WGS)　reaction.　The　catalysts　were　characterized　by　XRD,　BET,　H2-TPR　and　cyclic　voltammetry　(CV)　techniques.　The　results　indicate　that　catalytic　activity　increases　with　the　aluminum　content　at　first,　but　then　decreases　with　the　further　increase　of　aluminum　content.　Hereinto,　Cu/CeO　2　catalyst　doped　with　1　wt.%　of　aluminum　shows　the　highest　catalytic　activity　(CO　conversion　reaches　84.4%　at　200　°C)　and　thermal　stability　for　WGS　reaction.　Correlation　to　the　results　from　above　characterization,　it　is　found　that　the　variation　of　catalytic　activity　is　in　very　agreement　with　that　of　the　surface　area,　the　area　of　peak　γ　(i.e.,　the　reduction　of　surface　copper　oxide　(crystalline　forms)　interacted　with　surface　oxygen　vacancies　on　ceria),　and　the　area　of　peak　C2　and　A1(Cu0　↔　Cu2+　in　cyclic　voltammetry　process),　respectively.　Enough　evidence　was　found　for　the　fact　that　the　metallic　copper　(Cu0)　interacted　with　surface　oxygen　vacancies　on　ceria　is　the　active　site　for　WGS　reaction　over　Cu/CeO2　catalysts.　©　2007　Springer　Science+Business　Media,　LLC.