Zeolite T/6FDA-durene mixed matrix membranes are fabricated for CO2/CH4 separation. Effect of zeolite T loading on physical properties and gas separation performance are studied. Zeolite T enhances gas permeation properties of the resultant MMMs. The MMM improves CO2 plasticization resistance up to 300%. The membrane has successfully surpassesed the 1991 Robeson's upper bound.