The effects of Co on RuO2/Al2O3's activities for water gas shift (WGS) and methanation were studied. Catalysts were characterized with BET, XRD, SEM/EDS, H-2-TPR and CO-TPR. The effects of various parameters, such as calcination temperature, Ru-Co loading, Ru/Co ratio, inlet CO concentration and H2O/CO ratio on the activities of catalysts were investigated. There existed Col (strongly interact with RuO2) and Con (weakly interact with RuO2). For Co/RuO2/Al2O3 (Ru/Co = 1, AT = 350), only Co-I existed as bimetallic Co-Ru nanoparticles. This unique structure led this catalyst to achieve the highest CO conversion of 98.6% exceeding WGS's theoretical thermodynamic equilibrium limit due to the co-occurrence of methanation. Co/RuO2/Al2O3 was more favorable to catalyze CO methanation than CO2 methanation. The apparent activation energies of forward and reverse WGS catalyzed by Co/RuO2/Al2O3 were 37.8 and 74.6 kJ mol(-1), respectively. The difference was corresponding well to the enthalpy change (-41.1 kJ mol-1) of WGS. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.