A series of cross linked poly(ethylene oxide) (PEO) membranes with a multi armed and star like structure was prepared by photo polymerization The structure characterization was performed by Fourier transform infrared spectroscopy (FTIR). The thermal property was evaluated by differential scanning calorimetry (DSC). The inter segmental distance of polymer chain was investigated by wide-angle X-ray diffraction (WAXD). The density was determined by a hydrostatic weighing method. The permeation performances for N-2, CH4 and CO2 were reported. The relationship between gas permeation performances and physical properties was also discussed. The star -like PEO membranes exhibit excellent permeation separation performances for CO2/N-2 and CO2/CH4. The permeation separation performance for CO2/N-2 exceeds the Robeson upper boundary The star-like PEO membranes display a positive potential application for industrial scale CO2 separation. (C) 2015 Elsevier B.V. All rights reserved.