A dual phase membrane of 60 wt % Ce0.9Gd0.1O2-delta-40 wt % Ba0.5Sr0.5Co0.8Fe0.2O3-delta (60CGO-40BSCF), which exhibits high oxygen permeation, has been prepared. X-ray diffraction (XRD) results reveal that the two oxides are compatible. An oxygen permeation flux of 2.1 mL/(min.cm(2)) is obtained with a 0.5 mm thick membrane under the gradient of air/He at 975 degrees C, which keeps steady during 180 h of operation. The oxygen permeation process is mainly controlled by the bulk diffusion of oxygen ions in 60CGO-40BSCF membrane when the membrane thickness is higher than 0.8 mm and controlled by both the surface reaction and the bulk diffusion at reduced thickness of similar to 0.5 mm as the temperature increased from 800 to 975 degrees C.