In　this　study,　magnesium　matrix　composites　reinforced　with　different　loading　of　AlN　particles　were　fabricated　by　the　powder　metallurgy　technique.　The　microstructure,　bending　strength　and　fracture　behavior　of　the　resulting　Mg-Al/AlN　composites　were　investigated.　It　showed　that　the　5　wt%　AlN　reinforcements　led　to　the　highest　densification　and　bending　strength.　The　total　strengthening　effect　of　AlN　particles　was　predicted　by　considering　the　contributions　of　CTE　mismatch　between　the　matrix　and　the　particles,　load　bearing　and　Hall-Petch　mechanism.　The　results　revealed　that　the　increase　of　dislocation　density,　the　change　of　Mg17Al12　phase　morphology,　and　the　effective　load　transfer　were　the　major　strengthening　contributors　to　the　composites.　The　fracture　of　the　composites　altered　from　plastic　to　brittle　mode　with　increasing　reinforcement　content.　The　regions　of　clustered　particles　in　the　composites　were　easy　to　be　damaged　under　external　load,　and　the　fracture　occurred　mainly　along　grain　boundaries.　(C)　2016　Published　by　Elsevier　Ltd　on　behalf　of　The　editorial　office　of　Journal　of　Materials　Science　&　Technology.