To date, as the global demands for efficient gas separation techniques with minimum impact on the environment have been raised, gas separation technologies based on polymeric membranes have drawn attentions low cost and environmentally friendly alternatives. The key to a successful membrane is the identification and selection of materials which guarantee the membrane’s high performance for the target application. A wide range of polymeric materials can be used for membrane fabrication. However, since neat polymeric membranes show a trade-off between permeability and selectivity, hybrid membranes designated as mixed matrix membranes (MMM) have emerged as promising candidates as they combine the good processability, mechanical properties and low cost of polymers with the high gas separation properties of inorganic adsorbent fillers. In this study, MMM based on 6FDA-ODA polyimides and flexible crystalline metal-organic frameworks(MOF) of MIL-53(Al) and MIL-53(Al)–NH2 were prepared and characterized for CO2/CH4 and CO2/N2 separation. The synthesized MOF were characterized by XRD, SEM, ATR-FTIR and N2 adsorption at 77K, while the membranes were studied by ATR-FTIR and SEM to investigate their chemical structure and morphology, TGA for thermal and DMA for mechanical properties. Finally, single and mixed gas permeation tests were performed to determine the separation performance of these MMM.