A new series of Al 2 O 3 -doped SrCo 0.8 Fe 0.2 O 3−δ (SCFA) mixed conducting oxides were synthesized by the conventional solid-state reaction method. Effects of doping Al 2 O 3 (1, 3, 5 and 10wt.%, respectively) on the crystal structure, order–disorder phase transition, microstructure, oxygen permeability and structure stability of SrCo 0.8 Fe 0.2 O 3−δ (SCF) were investigated by XRD, TG-DSC, SEM, oxygen permeation measurement and the partial oxidation of methane (POM) to syngas reaction. Although the oxygen permeability of the SCF was weakened in the oxygen permeation measurement at the air/He gradient due to the doping of Al 2 O 3 , perovskite structure of SCFA was found stable in the low oxygen partial pressure (about 1.01325×10 2 Pa (10 −3 atm)). In the POM reaction, the rate of the oxygen permeation of SCFA3 (the addition amount of Al 2 O 3 was 3wt.%) membrane was about 10 times higher than that in the oxygen permeation measurement at 1223K, and the SCFA3 membrane was successfully operated in the POM reaction for more than 500h without fracture.