Double-filled　skutterudite　compounds　CemLanFeCo3Sb12　with　(m+n)=0.2-0.4　were　synthesized　by　spark　plasma　sintering　using　powders　of　Co,　Sb,　Fe,　and　rare-earth　Ce　and　La　as　starting　materials,　and　the　thermoelectric　properties　were　studied　in　detail.　The　dominant　phases　of　all　the　samples　are　the　skutterudite　with　small　amount　of　Sb　as　an　impurity　phase,　and　the　amount　of　Sb　decreases　in　double-filled　compound.　The　lattice　constant　is　enhanced　linearly　up　to　(m+n)=0.30　with　increasing　filling　fraction　and　then　unchanged.　The　Seebeck　coefficient　and　thermal　conductivity　of　double-filled　compounds　are　generally　higher　than　single-filled　samples　whatever　the　filling　fraction　is.　Among　all　the　samples,　Ce0.1La0.2FeCo3Sb12　shows　the　highest　Seebeck　coefficient　of　150　mu　V　K-1　at　773　K　and　the　lowest　thermal　conductivity　of　1.81　W/mK　at　673　K,　and　the　maximum　ZT　value　reaches　0.60　at　773　K　due　to　its　lower　thermal　conductivity.　(c)　2005　American　Institute　of　Physics.