Mg-Zn-Zr　(ZK60)　alloys　reinforced　by　ultra-low　content　(＜　0.1　wt%)　of　graphene　nanoplatelets　(GNPs)　were　fabricated　via　stirring　cast　and　extrusion　processes.　In　composites,　GNPs　thoroughly　dispersed　and　continuously　combined　with　Mg　matrix　at　the　interface,　beneficial　for　the　load　and　heat　transfer　of　composites.　The　static　and　dynamic　mechanical　properties　of　GNP/ZK60　composite　were　investigated　and　respectively　compared　with　those　of　ZK60　alloy.　With　only　0.04　wt%　addition,　GNP　nanofillers　improved　the　impact　toughness　twice　that　of　ZK60　matrix　up　to　17　J　cm(-2).　In　tensile　test,　GNP(0.04)/ZK60　composite　performed　enhanced　tensile　yield　strength　of　256　MPa,　improved　by　62%　than　ZK60　alloy.　Although　grain　boundary　is　commonly　considered　as　defect　to　deteriorate　transport　property,　GNP(0.04)/ZK60　composite　with　largely　refined　grain　size　conducted　superior　thermal　conductivity　of　139.4　W.(mK)(-1)　than　ZK60　alloy　(132.2　W.(mK)(-1))　at　room　temperature.　The　dispersed　GNPs　in　matrix　provide　beneficial　networks　for　efficient　load　and　heat　transfer.　This　work　explores　that　graphene　reinforcement　is　an　effective　way　to　simultaneously　improve　the　mechanical　and　thermal　properties　of　Mg　alloys　for　enlarged　applications.