The electrolyte materials Ce0.85Sm0.15O1.9 (SDC) and La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) are synthesized by glycine-nitrate processes, respectively. Then SDC-LSGM composite electrolytes are prepared by mixing SDC and LSGM. The SDC and LSGM powders are mixed in the weight ratio of 95:5, 90:10 and 85:15 and named as SL9505, SL9010 and SL8515. SEM shows the grain size of SDC-LSGM composites increased distinctly. The electrical properties of SDC and SDC-LSGM composites are investigated. The grain boundary resistance could be significantly decreased by small addition of LSGM. The experimental results show that the SDC-LSGM composites exhibit excellent conductivity and could significantly enhance the fuel cell performances. Among these electrolytes. SL9505 has the highest conductivity and the maximum power density. (C) 2012 Elsevier B.V. All rights reserved.