The　Ba-,　La-　and　Ag-doped　polycrystalline　Ca2.9M0.1Co4O9(M=Ca,　Ba,　La,　Ag)　thermoelectric　bulk　samples　were　prepared　via　citrate　acid　sol-gel　synthesis　method　followed　by　spark　plasma　sintering　technique.　The　bulk　samples　were　characterized　and　analyzed　with　regard　to　their　phase　compositions,　grain　orientations　as　well　as　microstructures.　The　high　temperature　thermoelectric　transport　properties　of　the　bulk　samples　were　studied　in　detail.　All　bulk　samples　were　found　to　be　single-phased　with　modified　body　texture.　The　electrical　resistivity　was　modulated　as　a　result　of　carrier　concentration　modification,　however　the　carrier　transport　process　was　not　influenced;　the　Seebeck　coefficient　was　deteriorated　simultaneously.　The　total　thermal　conductivity　was　remarkably　reduced,　on　account　of　the　decreasing　of　phonon　thermal　conductivity.　The　thermoelectric　properties　of　the　Ba-,　La-,　and　Ag-doped　bulk　samples　were　optimized,　and　the　Ba-doped　Ca2.9Ba0.1Co4O9　system　was　found　to　have　the　highest　dimensionless　figure　of　merit　ZT　0.20　at　973　K,　which　was　remarkably　higher　than　that　of　the　un-doped　sample.