Carbon molecular sieve membrane (CMSM) was prepared by dip coating a phenol formaldehyde novolac resin (PFNR) based green membrane support with an ethanol solution containing PFNR and carbon molecular sieve (CMS). X-ray diffraction and nitrogen adsorption isotherms were employed to characterize the carbon structures. The results indicated that the CMSM shows high selectivity for separation of gases like O-2/N-2 and H-2/CH4 system from pure gas permeation experiments. The permeation rate of H-2, O-2, and CO2 increases with the addition of CMS to the coating agent, while that of N-2 and CH4 decreases. Correspondingly, the ideal separation factor of H-2/CH4 enhances from 316 with a 50 wt.% PFNR ethanol solution as coating agent to 468 with a 50 wt.% PFNR ethanol solution involving CMS as coating agent, representing an increase of 48%. The addition of CMS redounds to the permeation of O-2 and reduction of defect in the carbon membrane. (c) 2006 Elsevier B.V. All rights reserved.