▎ 摘　　要

NOVELTY - Preparing a gas separation film, comprises mixing graphene and N,N-dimethylformamide to obtain a mixture and then ultrasonically dispersing, mixing the mixture with 1,4-butanediol, 4,4-diphenylmethane diisocyanate and dibutyltin dilaurate in a water bath and then heating at temperature of 40-50 degrees C, carrying out polymerization reaction of the heated mixture to obtain reaction liquid, coating the reaction liquid in a porous support and then heat treating at temperature of 50-70/oC for 10-20 hours. USE - The method is useful for preparing a gas separation film (claimed). ADVANTAGE - The method is capable of preparing the film with increased gas separating property and improved dispersibility. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a gas separation film obtained by the above method.