SiC　particulate　reinforced　magnesium　matrix　composites　SiCp/AZ31　were　successfully　prepared　by　repeated　plastic　working　(RPW)　combining　with　hot　extrusion.　Effects　of　cycling＇s　times　(times　of　RPW)　on　microstructure　and　properties　of　the　composites　were　investigated.　The　results　indicate　that　the　RPW　can　refine　grain　sizes　of　AZ31　alloy　and　SiC　particles,　and　uniformly　distribute　the　SiC　particle　in　the　matrix　alloy.　In　addition,　it　can　not　only　remarkably　enhance　tensile　strength　and　hardness　of　the　composites,　but　also　improve　its　plasticity.　With　4%　SiC　particle　in　volumetric　fraction,　the　ambient　tensile　strength　and　hardness　of　the　composites　can　reach　up　to　359MPa　and　107,　respectively,　after　300　times　RPW　cycling　by　hot　extrusion,　in　which　grain　size　of　the　matrix　alloy　is　refined　to　20　μm　and　SiC　particles　are　refined　to　below　3　μm,　dispersedly　distributed　in　the　matrix　alloy.