The invention relates to a solid oxide fuel cell taking sludge thermal gas as fuel and a generating method thereof, belonging to the field of solid oxide fuel cells. A YSZ (Yttria Stabilized Zirconia) membrane divides a shell into an anode chamber and a cathode chamber, the anode chamber is internally provided with a thermal gas pipe, the cathode chamber is internally provided with an air pipe, an anode and a cathode are respectively fixed at two sides of an electrolyte membrane, and the sludge thermal gas is taken as the fuel. The generating method comprises the following steps of: desulphurizing by virtue of the sludge thermal gas, absorbing carbon dioxide, mixing the carbon dioxide with the air, then introducing the mixed gas into the anode chamber to carry out oxidation reaction and introducing the air into the cathode chamber to carry out reduction reaction, and outputting a current. The solid oxide fuel cell provided by the invention has the generating efficiency of 200-400mW/cm<2>; and the performance of the solid oxide fuel cell after 40-60 hours is reduced by 5-10% only, thus stable current and voltage can be provided.