La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) tubular membranes with relative density more than 95% were prepared using plastic extrusion method, and their oxygen permeation properties were characterized in steady state. It was found that the permeation properties were influenced apparently by the sintering temperature for the resulting LSCF membranes. The as prepared LSCF membrane sintered at 1300oC had a permeation rate by 5~6 times higher than that sintered at 1250oC. The XRD results showed that the as prepared LSCF membrane sintered at 1250oC had the content of impurity more than that sintered at 1300oC. Namely the reasonable elevation of sintering temperature can reduce the impurity in LSCF membranes, which was produced during green process, and the effect of impurity reduction can improve the transport capability of LSCF membranes made by plastic extrusion.