Ce1−x Sm x O2−1/2x nanopowders were successfully synthesized by microwave-induced combustion process. For the preparation, cerium(III) nitrate hexahydrate, samarium(III) nitrate hexahydrate, and urea were used for the microwave-induced combustion process. The process took only a few minutes to obtain Ce1−x Sm x O2−1/2x powders. Ce1−x Sm x O2−1/2x ceramics prepared by microwave-induced process sintered at 1400°C for 3h, the bulk density of Ce1−x Sm x O2−1/2x ceramics were over 95% of the theoretical density. The results revealed that Ce0.84Sm0.16O1.92 possessed the maximum electrical conductivity was 0.0287Scm−1 at 850°C and the minimum activity energy, E a was 0.9565eV determined from 500 to 850°C.