NOVELTY - A biomass gasification furnace comprises furnace (7), refraction circuitous supply device (3), suspended board type fuel gas filter (4), secondary heating and purifying device and reclaim device (6); mid lower part of cavity of furnace (7) is oxidation layer (1), lower part of cavity of furnace (7) is slag layer (9); where refraction circuitous supply device (3) is set in oxidation layer (1) of furnace (7) cavity, suspended board type fuel gas filter (4) is mounted on outside of furnace (7) and its bottom is inter-connected with secondary heating and purifying device (5).    USE - The biomass gasification furnace is used for gasification.    ADVANTAGE - Current stalk fuel gas stove burns oxygen directly and tar waste water generated by the stove is drained out, when the stalk is burned in the stove, the burning time is short, heating capacity is poor and causes peculiar smell, so this stove is not capable for cooling and warming closed house at the same time at north area; but this biomass gasification furnace does not have such problems. A refraction circuitous supply mode is adopted in this biomass gasification furnace, terminal of the refraction circuitous supply device is covered with a shield, thus oxygen enters in slag layer from a negative direction and distributed evenly through oxidation hole for burning; so burning stable and can generate gas for a long time.    DETAILED DESCRIPTION - A biomass gasification furnace comprises furnace (7), refraction circuitous supply device (3), suspended board type fuel gas filter (4), secondary heating and purifying device and reclaim device (6); mid lower part of cavity of furnace (7) is oxidation layer (1), lower part of cavity of furnace (7) is slag layer (9); where refraction circuitous supply device (3) is set in oxidation layer (1) of furnace (7) cavity, suspended board type fuel gas filter (4) is mounted on outside of furnace (7) and its bottom is inter-connected with secondary heating and purifying device (5), the secondary heating and purifying device (5) is mounted on outside of furnace (7) and inter-connected with suspended board type fuel gas filter (4), one end of reclaim device (6) is connected with lower part of the suspended board type fuel gas filter (4), and another end of the reclaim device (6) is inter-connected with slag layer (9).    DESCRIPTION OF DRAWING(S) - The drawing shows the front view of the biomass gasification furnace.    Oxidation layer (1)    Refraction circuitous supply device (3)    Gas filter (4)    Furnace (7)    Slag layer (9)    Tooth (31)