Abstract: The reactions of low and medium concentration dry methane over the anode of solid oxide fuel cell (SOFC) with Ni/yttria-stabilized zirconia(YSZ) anode and YSZ electrolyte were studied. The production rates of gases at anode outlet were measured at different current densities. Mass balance and the relations of production rates with reaction rates were used to analyze the chemical and electrochemical reactions taking place in parallel. For low concentration dry methane，partial oxidation of methane occurred at a low current density，electrochemical oxidations of hydrogen and carbon monoxide took place with the increasing current density. For medium concentration methane，only partial oxidation of methane occurred. Carbon deposition was found in all the tests.