NOVELTY - Agricultural resources, poultry manure, organic waste and organic solid waste are provided as raw material for biomass fuels. The raw material is dehydrated and gasified by combusting at 550-650 degrees C, to obtain gaseous product (g1). The gaseous product (g1) is separated, subjected to cracking reaction by adding catalyst, and tar components are removed, to obtain gaseous product (g2). The obtained product is mixed with oxygen, combusted using steam boiler, and three-dimensional surrounding-type heat is formed. The obtained heat is provided into a turbine, to generate electricity.    USE - Power generation (claimed).    ADVANTAGE - The method enables economical and environmentally-friendly power generation by biomass gasification with high combustion rate and high power generation efficiency, by producing reduced amount of biomass ash, carbon, smoke and dust.    DETAILED DESCRIPTION - Agricultural resources, poultry manure, organic waste and organic solid waste are provided as raw material for biomass fuels. The raw material is dehydrated to water content of 30% or less and gasified by combusting at 550-650 degrees C, to obtain gaseous product (g1). The gaseous product (g1) is separated, transferred for every 15 minutes, and unburned materials are combusted until residual material is 5% of the total raw material. The separated gaseous product (g1) is subjected to cracking reaction by adding catalyst at 800-1200 degrees C, and tar components are removed, to obtain gaseous product (g2). The obtained product is mixed with oxygen in volume ratio of 1:3-1:5, combusted using steam boiler, and three-dimensional surrounding-type heat is formed. The obtained heat is provided into a turbine, to generate electricity. The agricultural resources comprises firewood, timber, biogas, rice husk, bark, weeds, corn stalks, corn cob, rice straw, wheat straw, peanut shell, sugarcane dregs and cottonseed hull. The organic waste comprises domestic wastewater, alcoholic wastewater, sugar refining wastewater, pharmaceutical wastewater and papermaking wastewater.