The　particles　of　Mg-Zn-Gd　icosahedral　quasi-crystal　master　alloy　were　added　into　the　AZ31　alloy　by　the　repeated　plastic　working　(RPW)　process　in　order　to　improve　the　mechanical　properties　of　the　AZ31　alloy　at　room　temperature.　The　microstructure　and　tensile　properties　of　composites　were　investigated　by　scanning　electron　microscopy　(SEM),　transmission　electron　microscopy　(TEM),　X-ray　diffraction　(XRD),　and　tensile　testing　machine　at　room　temperature.　The　results　suggest　that　the　RPW　process　can　effectively　refine　the　matrix　and　make　the　I-phase　particles　distribute　uniformly.　The　ultimate　tensile　strength　and　the　yield　strength　of　the　composites　reach　their　maximum　values　of　362.3　and　330.5MPa,　respectively,　when　the　amount　of　I-phase　particles　added　is　10%.　Meanwhile,　the　elongation　of　the　composites　decreases　sharply.