The objective of this study is to develop a gas pro-treatment system for DME synthesis, wherein this system separates CO2 from Flaring gas as Membrane, in order to save raw material (CH4) cost of DME. In this study, hollow fiber membrane is developed, which is able to separate high-pressure gas, supported by polysulfone and coated with amorphous fluorinated polymer. Throughout the evaluation of the membrane’s separation characteristics, the membrane is applied to this system. The membrane is designed by 2 stages for over 90% removal rate of CO2 and over 90% recovery rate of CH4. The bench scale of pro-treatment system is developed as 25 N㎥/hr.