Abstract: Tar in gas product from biomass gasification would block the downstream equipments and affact the gasifier operating. It is important to understand the tar evolving and cracking behavior in the fluidized bed gasifier. With peanut shell, rice straw and saw dust as raw materials, the gasification was carried out in a pilot scale fluidized bed gasifier at variant temperatures (750℃～850℃), air equivalence ratio(0.15～0.35) and catalyst addition. Simultaneously, tar component was analyzed using gas chromatograph with mass selective detector (GC-MS). It is observed that the tar content decreases obviously with temperature increasing, and the catalyst addition also displays a similar result, which is attributed to the cracking of heavy components in tar. Higher temperature and catalyst are effective for the controlling and removing of tar during biomass gasification.