Multiple-doped skutterudites SmmCenFe1.5Co2.5Sb12 were prepared by melting and spark plasma sintering method, and the effects of doping atoms Sm and Ce on the thermoelectric properties of these compounds were investigated. For p-type SmmCenFe1.5Co2.5Sb12, with the Sm and Ce multiple-doping amount increasing, the electrical conductivity and the thermal conductivity decrease and the Seebeck coefficient increases. When the doping amount is similar, in comparison with the Sm or Ce doping, the Sm and Ce multiple-doping can lower the thermal conductivity of skutterudites 10%—40%. At 775K, the ZTmax value of 0.84 was obtained for Sm0.22Ce0.20Fe154Co2.46Sb11.89.