Abstract: Currently，the mainly technical problems are poor material adaptability, high content of tar and low heat value of product gas during the popularization and application of biomass gasifiers. In this paper, a new biomass gasifier was put forward, in which porous ceramics material inlayed an air guide of U-shaped tube. The experiments results indicated that, when straw stalk of moisture content 12.3% was used, the tar content was reduced to 0.02～0.06 g/m3, average gasification efficiency could reach up to 61.9% and average low heat value of producer gas was about 5.0 MJ/m3. The new structure of biomass gasifier is helpful to obtain high quality gas with lower tar content and higher heat value.