Polymeric gas separation membrane is the fastest growing field in membrane separation process. Polymeric gas separation membrane process is competitive compare to cryogenic process and pressure swing adsorption process. Aromatic polymer materials such as polysulfones, polypheneylene oxides, polycarbonates and polyimides have been used for gas separation. Recently, glassy polymer likes polyimide in aromatic polymers has been developed for achievement of high selectivity and permeability coefficients. The accurate understanding on a type and structure of polymer material is very important, because the factor that polymer material affect gas separation property. In the study, trend and the development direction on synthesis and permeation properties of polyimide is confirmed.