NOVELTY - Processing synthesis purge gas comprises (A) first film separating procedure; (b) alternating procedure; (C) decarbonizing procedure; and (D) second film separating procedure. The step (A) includes performing first film separation to methanol synthesis purge gas, obtaining hydrogen rich gas flow and target gas flow, where methanol synthesis purge gas comprises hydrogen, carbon monoxide, carbon dioxide, methane, and nitrogen. The step (B) includes performing transforming reaction to carbon monoxide and transforming to be carbon dioxide, generating hydrogen, and obtaining target gas flow.    USE - Method is used for processing synthesis purge gas (claimed).    ADVANTAGE - The method can effectively recycle hydrogen and carbon monoxide in methanol synthesis purge gas as compared with conventional method; and fully utilizes light hydrocarbon gas such as methane in purge gas.    DETAILED DESCRIPTION - Processing synthesis purge gas comprises (A) first film separating procedure; (b) alternating procedure; (C) decarbonizing procedure; and (D) second film separating procedure. The step (A) includes performing first film separation to methanol synthesis purge gas, obtaining hydrogen rich gas flow and target gas flow, where methanol synthesis purge gas comprises hydrogen, carbon monoxide, carbon dioxide, methane, nitrogen and the other light hydrocarbon. The step (B) includes performing transforming reaction to carbon monoxide and transforming to be carbon dioxide, generating hydrogen, and obtaining target gas flow. The step (C) includes absorbing carbon dioxide using solvent to remove, obtaining third target gas flow. The step (D) includes performing second film separation to third target gas flow and obtaining second hydrogen rich gas flow and fourth target gas flow. The purge gas is methanol synthesis purge gas and/or synthetic ammonia purge gas.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic flow diagram illustrating a method for processing synthesis purge gas. (Drawing includes non-English language text).