The　mechanical　properties　of　3D　printed　alumina　ceramics　are　degraded　due　to　the　micro　anisotropy,　interlayer　interface　defects　and　microporous　characteristics.　In　order　to　improve　its　mechanical　properties,　solid　phase　sintered,　liquid　phase　sintered　and　solid-liquid　phase　sintered　alumina　(Al2O3)　ceramics　were　prepared　by　Vat　photopolymerization　3D　printing　technology,　respectively.　In　the　experiment,　Al2O3　was　used　as　the　main　material　to　study　the　effects　of　TiO2　solid　phase　additive,　MgO-SiO2　liquid　phase　additives　and　TiO2-MgO-SiO2　solidliquid　phase　additives　on　Al2O3　ceramics　sintering　behavior　and　mechanical　properties,　so　as　to　improve　the　sintering　density　and　mechanical　properties　of　alumina　ceramics.　The　best　composition　ratio　and　sintering　temperature　were　determined　by　shrinkage,　relative　density,　Raman,　XRD　and　SEM　characterization.　Under　optimal　sintering　conditions,　The　comprehensive　properties　of　Al2O3　ceramics　prepared　by　liquid　phase　sintering　are　more　balanced.　And　has　excellent　mechanical　properties.　The　flexural　strength　reached　317　+/-　34　MPa　and　the　Vickers　hardness　up　to　1250　+/-　102　HV30.　Thus,　nine　types　of　truss　structures　are　prepared　to　study　their　mechanical　properties.　By　changing　the　structure　types,　the　order　of　compressive　strength　is　FCC　＞　BCC　＞　DLS.　By　changing　the　number　of　units,　the　order　of　compressive　strength　is　3　x　3　x　3　units　＞2　x　2　x　2　units　＞1　x　1　x　1　units.　The　Al2O3　ceramics　prepared　by　the　liquid　phase　sintering　exhibit　excellent　mechanical　compression　properties　and　energy　absorption　capacity.　The　FCC　structure　of　3　x　3　x　3　units　can　reach　23.2　+/-　1.7　MPa　compressive　strength.