Cobalt-free oxides GdxBa1-xFeO3-delta (0.01 <= x <= 0.1) were achieved by a solid state reaction method. It is found that GdxBa1-xFeO3-delta (0.025 <= x <= 0.1) exhibits the cubic perovskite structure. Among GdxBa1-xFeO3-delta (0.025 <= x <= 0.1), the Gd0.025Ba0.975FeO3-delta (GBF2.5) membrane shows the outstanding phase structure stability and the highest oxygen permeation, which can reach 1.44 ml.cm(-2).min(-1) at 950 degrees C under air/He oxygen partial pressure gradient. The GBF2.5 membrane was successfully operated for more than 100 h at 800 degrees C and the oxygen permeation flux through the membrane is 0.62 ml.cm(-2).min(-1). After 100 h oxygen permeation experiment at 800 degrees C, X-ray diffraction (XRD) and energy dispersive X-ray spectrometer (EDXS) demonstrate that the GBF2.5 exhibits phase structure stability even at intermediate temperature. (C) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.