Abstract: The solid-state reaction method was used to prepare the perovskite oxide SmCoO₃.The structure and properties of the samples have been investigated by XRD，Raman spectral techniques and DC measurements and so on.The XRD and Raman spectra show that the mixtures of Co₂O₃ and Sm₂O₃ can form a single-phase perovskite oxide SmCoO₃ by solid-state reaction around 1353K.The clearly observed band in the room temperature Raman spectra of single-phase SmCoO₃ is at 140~175cm^-1,，which is assigned to the stretching of Sm—O and the winding of O—Sm—O.The single-phase SmCoO₃is an insulator below 600K，and the conductivity is enhanced obviously with temperature increasing above 600K.This may be explained by the fact that an insulator to semiconductor transition occurs around 470K.The thermal expansion coefficient（2.17×10^-5,K^-1,）of the single-phase SmCoO₃is approximately equal to that of doped LaGaO₃，but bigger than that of SDC（Ce_0.85Sm_0.15O₂）above 873K.

Key words: SmCoO₃, solid-state reaction, cathode material, structure characteristic, conductivity