NOVELTY - Preparing hydrogen from biogas, comprises: (a) heating biogas using first heat exchanger and controlling total sulfur content in gas; (b) heating desulfurized gas using second heat exchanger and introducing to pipe passage; (c) conveying gas into carbon monoxide exchanger to react with overheat vapors and separating to get product and device tail gas; (d) conveying tail gas into shell passage for catalytic combustion; and (e) conveying obtained high-temperature smoke into first heat exchanger and then to vapor generator, and conveying obtained overheat vapor to carbon monoxide exchanger.    USE - The method is useful for preparing hydrogen from biogas.    ADVANTAGE - The method: has simple process; improves heat utilization rate of device; and is economical.    DETAILED DESCRIPTION - Preparing hydrogen from biogas, comprises: (a) heating biogas material to 340-360 degrees C using a first heat exchanger, introducing to a desulfurization reactor for desulfurization, controlling total sulfur content in the gas under 20 mg/m3; (b) heating desulfurized gas to 580-600 degrees C using a second heat exchanger, introducing to a pipe passage of a tube-and-shell reactor for reforming reaction in the presence of catalyst; (c) conveying the gas into a carbon monoxide exchanger through the second heat exchanger for reacting with overheat vapors and then conveying the obtained gas into a membrane separator for separating to obtain product and device tail gas; (d) conveying the device tail gas into a shell passage of the tube-and-shell reactor to occur catalytic combustion reaction with air in presence of the catalyst; and (e) conveying high-temperature smoke obtained through the catalytic combustion reaction into the first heat exchanger and then conveying to a vapor generator for heating desalted water, and using the obtained overheat vapor as reaction gas to convey into the carbon monoxide exchanger.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the process for preparing hydrogen from biogas (Drawing includes non-English language text).