The　lamellar　and　orientational　characteristics　of　graphene　nanoplatelets　(GNPs)　are　crucial　for　reinforcing　metal　matrix　composites,　particularly　in　terms　of　their　thermal　properties.　Two　kinds　of　GNPs　with　plane　sizes　of　6　&　mu;m　and　80　&　mu;m　were　respectively　used　as　reinforcements　in　ZK60　alloy　by　powder　metallurgy.　The　oriented　distribution　of　GNPs　in　the　matrix　was　obtained　using　a　double-pass　hot　extrusion　process,　i.e.,　a　stepped　extrusion　with　two　consecutive　extrusion　ratios　(10:1　and　16:1).　Reinforced　with　0.05　wt%　oriented　GNPs　(80　&　mu;m),　the　composite　exhibited　a　tensile　yield　strength　of　257　MPa,　ultimate　tensile　strength　of　342　MPa,　elongation　of　24.7%,　and　notably　enhanced　thermal　conductivity　of　128.3　W　(mK)(-1)　even　with　refined　grain　size　compared　to　the　ZK60　alloy.　The　oriented　GNPs　in　the　matrix　create　a　favorable　path　for　efficient　load　and　heat　transfer,　leading　to　the　simultaneously　enhancement　of　mechanical　and　thermal　properties　of　the　GNPs/ZK60　composites.　This　work　is　expected　to　broaden　the　application　potential　of　GNPs　as　highly　efficient　reinforcements　and　provide　a　practical　method　for　fabricating　metal　matrix　composites.