Various　methods,　including　vacuum　sintering,　pressure-less　sintering　in　the　N-2　atmosphere　and　spark　plasma　sintering,　were　used　to　densify　the　AlN　ceramics,　and　effects　of　sintering　methods　on　the　sintering　behavior,　phase　composition,microstructure　and　thermal　conductivity　of　the　sintered　AlN　samples　were　investigated.　The　results　show　that　vacuum　sintering　can　remarkably　reduce　the　decomposition　temperature　of　AlN　which　makes　it　impossible　to　densify　the　samples,　while　the　other　two　methods　can　prepare　almost　fully　dense　samples　with　high　thermal　conductivity.　In　particular,　spark　plasma　sintering　is　a　better　way　to　clean　the　grain　boundary　and　obtain　denser　samples　with　a　high　thermal　conductivity　of　121.5　W.m(-1).K-1　at　a　lower　sintering　temperature　of　1650　degrees　C.