NOVELTY - Generating hydrogen and separating carbon dioxide based on iron or iron oxide comprises separating gas phase and solid phase, discharging separated mixed gas of hydrogen vapor, condensing, returning separated iron oxide, further oxidizing and recycling.    USE - Method for generating hydrogen and separating carbon dioxide based on iron or iron oxide (claimed).    DETAILED DESCRIPTION - Generating hydrogen and separating carbon dioxide (CO2) based on iron (Fe) or iron oxide (FeO) comprises placing Fe or FeO in a fluidized bed of an air reactor. Fluid air is introduced to the bed from a lower end (E) of the fluidized bed of the air reactor. The Fe or FeO is reacted with the oxygen in the air to form Fe2O3, then the gas phase is separated from solid phase using a separator. The separated air is discharged from an upper end (H) of an oxygen-poor air separator, and the separated Fe2O3 enters a fluidized bed of a fuel reactor via a first overflow well, and the Fe2O3 is entrained to a riser of the fuel reactor at first before entering the fluidized bed of the fuel reactor and is reacted with the unreacted synthesis gas from a mixed gasification reaction chamber in the riser of the fuel reactor, and the synthesis gas is converted into mixed gas of CO2 vapor while the Fe2O3 is converted into Fe3O4. The gas phase and the solid phase are separated using a carbon dioxide separator, and the separated mixed gas of carbon dioxide vapor is discharged from the upper end of the carbon dioxide separator, through condensation, clean carbon dioxide is obtained, while the unreacted Fe2O3 and the generated Fe3O4 are discharged from the lower end of the CO2 separator, and they enters a mixed gasification reaction chamber via a return groove. The solid fuel enters the mixed gasification reaction chamber via a spiral feeder, and the lower end (A) of the mixed gasification reaction chamber is introduced into vapor as gasification medium. The heat for gasifying the solid fuel and the vapor is provided with the Fe2O3 and Fe3O4, and the gasified synthesis gas has reduction reaction with the Fe2O3 and Fe3O4 to generate carbon dioxide and vapor, which rise to the lift tube of the fuel reactor together with the unreacted synthesis gas, while the Fe2O3 and Fe3O4 are reduced to FeO or Fe. The iron oxide containing FeO and Fe is overflowed to a fluidized bed of a hydrogen generating reactor via a second overflow well (2). Vapor is introduced from the lower end (C) of the fluidized bed of the hydrogen generating reactor as fluidized medium. The vapor is reacted with the FeO or Fe to generate hydrogen, and the FeO or Fe is oxidized to Fe3O4, and the gas phase and the solid phase are separated by a hydrogen separator. The separated mixed gas of hydrogen vapor is discharged from the upper end (F) of the separator, and is condensed to obtain pure hydrogen. The separated Fe3O4 returns the fluidized bed of air reactor via a third overflow well (4) and is further oxidized, realizing recycling it. An INDEPENDENT CLAIM is included for a device for generating hydrogen and separating CO2 based on Fe or FeO.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a device for generating hydrogen and separating carbon dioxide.    Fuel reactor (1)    Overflow wells (2-4)    Air reactor (5)    Lower ends (A, C, E)    Upper ends (F, H)