The invention relates to a biomass sawdust fuel burning furnace, comprising a chassis frame, an incinerator, a spitfire mechanism, a fuel supply mechanism, a fuel supply box, a power transmission mechanism and an oxygen supply mechanism, wherein the chassis frame is arranged on floor; the incinerator is fixed at one end of the chassis frame, the outer wall of the incinerator constitutes a jacket and is provided with a feeding hole and a combustion-supporting air introduction mechanism, and a cover is arranged on the top of the incinerator in a matching manner; the spitfire mechanism is connected with the upper side part of the incinerator in a matching manner; the fuel supply mechanism is arranged on the other end of the chassis frame, and comprises a pair of guide rails, a moving frame, a screw rod cylinder and an extrusion screw rod; the fuel supply box is arranged on the fuel supply mechanism; the power transmission mechanism is arranged on the other end of the chassis frame; and the oxygen supply mechanism is arranged on the other end of a stand. The biomass sawdust fuel burning furnace disclosed by the invention has the advantages of high combustion efficiency, large heating quantity, low ignition point and high heating property, is friendly to the environment, good for protecting non-renewable natural resources such as petroleum and coal to embody the circular sustainable development of economy, concise in structure and convenient and safe to use; and a combustion effect can be guaranteed by introducing dense biomass sawdust into a hearth.