Abstract: Based on the energy and exergy analysis method,this paper studies the main parameters of the circulating fluidized bed biomass gasification process. The influence of biomass types,gasification temperature,ratio of steam to carbon（S/C）and equivalence ratio（ER）on the exergy efficiency of the gasification system. Studies have shown that among the many influencing factors of circulating fluidized bed biomass gasification,the change of biomass type has the greatest impact on the exergy efficiency of the gasification system.The MBM gasification process with FC of 8.99% has the lowest exergy efficiency at 12.52%. The Jincheng coal gasification process with FC of 68.68% has the highest exergy efficiency at 59.95%. At the same time,the relationship between the difference between the energy efficiency and the exergy efficiency of the gasification system and the calorific value of the gas produced is found. The increase of other gasification parameters,gasification temperature,S/C and ER will increase the exergy efficiency and energy efficiency,but after reaching a certain level,the peak will appear and the temperature will decrease.