The Sm0.9Sr0.1AlO3-δ samples were prepared by solid-state reaction. Their microstructure, morphology, electrical properties and transport mechanism were studied by X-ray diffraction(XRD), scanning electron microscopy(SEM), alternating current impedance technology and oxygen concentration cell method, respectively. The relationship between sintering technology, relative density and conductivity was studied. The experimental results show that the Sm0.9Sr0.1AlO3-δ perovskite oxides with single tetragonal phase can be obtained when they are sintered at 1650℃. Among all the samples, Sm0.9Sr0.1AlO3-δ sample sintered at 1650℃ for 16h has the highest relative density of 96.7% and electrical conductivity of 1.3×10-2 S/cm at 900℃. The curves of ln(σT) against 1000/T reveal two straight lines intersecting at 670 ℃, showing the activation energy of conduction in the high temperature range(T>670℃) is lower than that in the low temperature range(T0.9Sr0.1AlO3-δ is a mixed conductor of oxygen ion and hole in air. Its oxygen ionic transference number is around 0.7 in the measuring temperature region, and slightly increases with increasing temperature. By means of oxygen ionic transference numbers measured in air, the relative contributions of ionic and electronic conduction are separated, and the results reveal that activation energy for oxygen ionic conduction of 0.95eV is lager than that for hole conduction of 0.84eV, and Sm0.9Sr0.1AlO3-δ has an oxygen ionic conductivity of 9.65×10-3 S/cm at 900℃.