The invention discloses a fluidized bed pyrolysis gasification device by adopting a biomass gas recirculation process. The device comprises a fluidized bed gasifying furnace body, and a gasifying agent supply structure, an anti-leakage type feeding structure and a biomass gas circulating structure which are formed in the bottom end of the fluidized bed gasifying furnace body. The fluidized bed gasifying furnace body comprises a conical heating section, a pyrolysis section, a conical diffusion section and a settling section. The gasifying agent supply structure comprises an isobaric air bellow, an air distributor, and a cap arranged on the isobaric air bellow; the biomass gas circulating structure comprises a high-temperature exhaust duct, a dust exhaust fan, an air inlet pipeline and an injection pipe; the high-temperature exhaust duct is formed in the conical diffusion section and is communicated with the upper part of the conical diffusion section; the dust exhaust fan is arranged on the high-temperature exhaust duct; the air inlet pipeline is arranged on the dust exhaust fan and is communicated with the upper part of the conical heating section; and the injection pipe is arranged on the end of the air inlet pipeline and extends into the conical heating section. The device disclosed by the invention has the advantages of high adaptability, high efficiency, energy conservation, flexible operation and simple structure.