Microstructural evolution and mixed electronic-ionic conduction properties of perovskite-type La0.6Sr0.4Co0.8Fe0.2O3 ceramics were investigated in the sintering temperature range 1100-1250℃. The results confirm the crucial role of sintering temperature on microstructure and mixed conduction properties. The improvement of the mixed conduction properties with the increased sintering temperature from 1100℃ to 1200℃ is ascribed to the development of densification. Further increase of the sintering temperature above 1200℃ declined the mixed conduction properties due to the generation of excessive liquid. With respect to the mixed conduction properties, the preferred sintering temperature was ascertained to be 1200℃ for La0.6Sr0.4Co0.8Fe0.2O3 ceramics. The La0.6Sr0.4Co0.8Fe0.2O3 ceramic sintered at 1200℃ exhibited an electrical conductivity of 1.26×103 Ω-1cm-1 and an oxygen ionic conductivity of 3.73×10-2 Ω-1cm-1 at 800℃.