Associated gas flaring is one of the most challenging energy and environmental problems facing the world today.Approximately 150 billion cubic meters of natural gas are flared in the world each year,representing a 15 to 20 billion dollar waste of natural resources and contributing 400 million metric tons of CO2 equivalent global greenhouse gas emissions[1].Associated gas is typically not as pure as pipeline or utility gas,which is almost methane.The proportion of methane in associated gas is typically between 60 to 95 percent.Associated gas also contains heavier volatile hydrocarbons,mainly ethane,propane,butane,and pentanes.These heavier hydrocarbons can be condensed and have a higher heat value.In addition,associated gas may contain water vapor,hydrogen sulphide(H2S),CO2,nitrogen,and other compounds[2,3].Associated gas purification methods have been developed by using absorption process(High pressure scrubbing process),adsorption process(pressure swing adsorption process),membrane process[4].In this study,polysulfone hollow fiber membrane was applied to associated gas purification process.The membrane was prepared through the dry-wet spinning process and the membrane module was prepared to check the performance of permeance and selectivity of CO2 and hydrocarbons[5,6].The separation and purification membrane module test was focused on CO2 and hydrocarbons concentration from associated gas with various operating conditions.A single stage module removed over 95% of hydrocarbon as a final concentration and over 15% of loss of hydrocarbons.To reduce the loss of hydrocarbons,multi-stage process was designed and tested and the result showed more than 95% purity of methane with less than 5% loss of methane.This paper describes the membrane process design for associated gas purification and its optimized operating conditions were also described.