High　thermal　conductivity　and　dense　AlN/CNT　composite　ceramics　with　additive　Y2O3　were　fabricated　by　spark　plasma　sintered　(SPS)　in　this　paper.　The　results　indicated　that　CNT　blocked　the　densification　process　in　a　certain　extent,　but　in　the　sintering　temperature　of　1700　degrees　C,　the　relative　density　of　composite　ceramics　were　more　than　97%　with　1-10%　volume　fractions　of　CNT.　The　content　of　additive　Y2O3　affected　the　thermal　conductivity　of　AlN/CNT　obviously.　The　thermal　conductivity　of　composite　material　linearly　decreased　when　the　content　of　CNT　increased　and　the　tubular　structure　of　CNT　had　been　destructed　during　once　sintering.　The　effects　of　the　CNT　structural　damage　to　the　thermal　conductivity　of　composite　ceramics　were　improved　by　adjusting　the　sintering　process.　The　thermal　conductivity　of　the　composite　ceramics　with　3%　volume　fractions　of　CNT　sintering　in　1550　degrees　C/3minx3　was　up　to　145W/m.K,　which　higher　than　the　single-phase　AlN　ceramics.