The invention provides a biomass direct combustion device integrating oxygen-rich combustion and flue gas recirculation. The device comprises a biomass boiler, a plurality of primary air bins, an air compression device, a secondary air and over-fire air system, a waste heat boiler, a flue gas purifying system and a flue gas recirculation system, wherein the air compression device is used for generating oxygen-rich air fed into the biomass boiler; the secondary air and over-fire air system is used for generating secondary air and over-fire air fed into the biomass boiler; and the flue gas recirculation system is used for separately mixing re-circulated flue gas with the secondary air and the over-fire air. According to the biomass direct combustion device provided by the invention, the flue gas recirculation system adopting oxygen-rich combustion and a special design can realize a higher burn-out rate, less NOx emission and lower in-furnace high-temperature corrosion risk, and has the effects of reducing total air volume, reducing flash ash quantity, reducing volume of the waste heat boiler and the like.