The invention provides a device and a method for recycling gasified and burned alkali for a straw pulp papermaking black liquor circulating fluidized bed and relates to the device and the method for recycling the alkali of papermaking black liquor. The device and the method are used for solving the problems that the prior art is difficult to be used for recycling the straw pulp papermaking black liquor, the auxiliary fuels are added to a recycling process and the running cost is increased. The device comprises a multi-effect evaporator, a disc evaporator, a thick black liquor tank, a pump, a spraying gun, a gasifying chamber, a feedback valve, a waste heat boiler, an air pre-heater, a bag-type dust collector, a draught fan, a cone valve, a heat exchange chamber, a dissolving tank, a causticizer, a chain plate type slag conveyor, a drier, a secondary air fan, a second gas-solid separator, a tar condensing tower, a spraying dehydrating tower, a sewage treatment plant, a water annular compressor, an air storage tank, a circulating ash distributing chamber and a circulating fluidized bed, wherein the dissolving tank is respectively communicated with the causticizer and the chain plate type slag conveyor and the chain plate type slag conveyor is communicated with the drier. The device provided by the invention is used for recycling the alkali of the straw pulp papermaking black liquor.