Since the 1970s, the climax of the 20th World despise gas separation membrane studies, all existing geometry can be a film-forming polymer materials in gas separation aspects were evaluated. The common problem is: all large membrane permeability coefficient, the choice factor is low. Those who choose high coefficient of film permeability coefficient which is low. To get both higher than the film material, it must begin with a polymer synthesized from a dedicated gas separation membrane. Polyimide With the above advantages, while the structure easier to design and synthesis, so called one of the main subjects of the gas separation membrane materials.