The　TiN/Al2O3　composites　were　synthesized　by　in　situ　reaction　using　Al　and　TiO2　as　starting　materials,　which　were　high　energy　milled　and　hot　pressed.　The　phase　formation　and　transformation　regularity　of　powders　during　the　high　energy　milling　process　and　post　heat　treatment　were　investigated　by　DTA,　XRD　and　SEM　with　the　thermodynamics　calculations.　Meanwhile　the　mechanical　properties　and　microstructures　of　the　composites　were　also　studied.　The　results　show　that　the　N-2　dissolves　in　the　powders　during　the　high　energy　milling　process　and　the　Ti2AlN　phases　form　in　the　post　heat　treatment.　When　the　temperature　raises　high　enough　the　Ti2AlN　decompose　to　form　TiN　phase,　which　is　helpful　to　its　densification　and　mechanical　properties　improving.　TiN-Al2O3　composites　with　excellent　properties　can　be　fabricated　by　hot　pressing　the　milled　powders　at　1300　degrees　C,　30　MPa　and　holding　60　min,　whose　bending　strength　is　850　MPa,　and　fracture　toughness　5.7　MPa.m(1/2;).