Direct oxidation of carbon on anode of a solid oxide fuel cell was investigated. The result showed that oxidation of carbon was minimally contributed by diffusion of oxygen anion via contact with solid anode. Whether carbon is in contact with the anode is not a major factor to cell performance. By contrast, the cell performance was determined by concentration of gaseous products from carbon in cell chamber. These results invoke a new concept for designing Direct Carbon Fuel Cell with solid oxide anode.