A metallic Ni catalyst has been prepared with nickel sponge and further promoted with YSZ (yttrium-stabilized zirconia) by an impregnation method. The catalysts are characterized by ICP, BET, SEM, XRD and H(2)-TPR, and then studied for the partial oxidation of methane to hydrogen. The influences of reaction temperature, CH(4)/O(2) ratios and gas hourly space velocity on the reaction rate are investigated. The catalyst characterization results show that the YSZ-promoted metallic Ni catalysts have high specific surface area; there is more NiO phase in the YSZ-promoted catalysts than in the metallic Ni catalyst; a mutual diffusion of Ni(2+) and Zr(4+) ions might happen between the NiO and YSZ phases. The reaction results show that the YSZ promotion increases the CH(4) conversion and the selectivities to H(2) and CO. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.