NOVELTY - The gasification of biomass, purification of gases, gas engine or gas turbine, and exhaust heat utilization process are carried out, to generate electricity from the biomass. The gasification of biomass comprises feed-in mechanism including spiral batch charger and gasification device. The fuel gas purification comprises removing dust, ash and tar. The purification sensible heat and remaining heat of the fuel generating electricity device are combined, and the boiler and over-heater are used to produces steam, and the gas turbine generates electricity.    USE - Method for generating electricity from biomass.    ADVANTAGE - The electricity is generated efficiently and economically by using biomass having strong adaptability, operating stability, high gasification efficiency.    DETAILED DESCRIPTION - The gasification of biomass, purification of gases, gas engine or gas turbine, and exhaust heat utilization process are carried out, to generate electricity from the biomass. The gasification of biomass comprises feed-in mechanism and gasification device. The feed-in mechanism adopts spiral batch charger, and the power device is electromagnetic speed regulation electric motor. The spiral batch charger feeds the material constantly, separates and seal the gasification furnace and outside effectively, and makes gas to enter the furnace only from blower. The electromagnetic speed regulation electric motor freely regulates biomass material feeding quantity, and the gasification adopts circular fluid bed gasification furnace or the other gasification furnaces operating constantly and mainly comprises air inlet machine, the gasification furnaces and slag-off helix. The biomass produces fuel gases by pyrolyzing at high temperature and aerified in the gasification furnace, and the content after gasification is discharged from the furnace in time using the slag-off helix. Then, the purification of the gases is carried out. The gases for generating electricity are used only after purification. The fuel gas purification comprises removing dust, ash and tar. The gas purification adopts multi-level dust removing technology, such as inertial dust separator, cyclone separating device, venture dust catcher and electric precipitation. After multi-level removing dust, the solid grain and micro-powder in the fuel gases is cleaned basically, and the tar in the fuel gases is adopted to absorption and water-washed. The main device used is tow serial-connection spray scrubber. The electricity generating device comprises fuel gas engine electromotor sets or gas turbine. The tail gas after generation is discharged at 500-600 degrees C, and the electricity generating device has air adding and pressurizing system, tail gas at 450-500 degrees C, and much energy can be reclaimed. The reminded heat reclaiming device is added after fuel gas generating device such as boiler, and the system efficiency is improved. In the biomass purification system, the large amount of heat is obtained in tail gases, and has high outlet fuel gas temperature such as 700-800 degrees C. The purification sensible heat and remaining heat of the fuel generating electricity device are combined, and the boiler and over-heater are used to produces steam, and the gas turbine generates electricity.