Perovskite La0.9Sr0.1FeO3 ceramics have been synthesized at 1250℃，1300℃ and 1350℃ by the conventional solid-state reaction technique. From their crystal structures determined by powder X-ray diffraction，we found that the lattice volume decreases with increasing sintering temperature. The scanning electronic microscope (SEM) images of surface microstructures of the samples show that the average grain size increases with increasing sintering temperature. The electrical resistivity and Seebeck coefficient have been measured between room temperature and 800℃. At low temperatures，the electrical resistivity shows a semiconductivity-like behavior. With further increasing of temperature，the electrical resistivity slightly increases. An adiabatic hopping conduction mechanism of small-polarons is suggested from the temperature dependence of the electrical resistivity，which has different activation energies at low and high temperatures. The Seebeck coefficient rapidly decreases with increasing temperature，and reaches a saturation value about 600℃. With further increasing of temperature，the Seebeck coefficient slightly increases. With the increase of sintering temperature，the electrical resistivity decreases，while the Seebeck coefficient increases. Therefore，the power factor increases with increasing sintering temperature. The highest power factor of 90 μW/K2m was obtained at 727℃ for sample sintered at 1350℃.