Polycrystalline　BaxAgyCa3-x-yCo4O9　bulk　samples　were　prepared　by　citrate　acid　sol-gel　and　spark　plasma　sintering　method.　The　grain　orientation,　microstructure　and　high　temperature　thermoelectric　properties　of　the　bulk　samples　were　systematically　studied.　Small　quantities　of　the　secondary　phase　Ag　precipitated　within　the　x　＜=　y　compound　sample　matrices,　the　grain　orientation　and　microstructure　of　Ca3Co4O9　could　be　optimized.　The　electrical　resistivity　was　decreased　and　the　thermal　conductivity　was　increased　by　increasing　y/x　ratio.　The　x=y=0.1　sample　exhibited　lowest　electrical　resistivity　(7.2　m　Omega　cm　at　973　K)　and　thermal　conductivity　(1.41　W/mK　at　973　K)　simultaneously　with　high　Seebeck　coefficient　(172　mu　V/K　at　973　K),　the　dimensionless　figure　of　merit　could　reach　0.29　at　973　K.　(C)　2009　Elsevier　B.V.　All　rights　reserved.