Aramid　fabric　has　been　widely　used　as　a　bulletproof　material　due　to　its　lightness　and　comfort.　However,　multiple　fabric　layers　must　be　used　in　one　body　armour,　inevitably　reducing　its　flexibility.　To　improve　the　ballistic　performance　of　single-layer　aramid　fabric,　we　innovatively　modify　the　fabric　with　polyethylene　(LDPE)　and　graphene/polyethylene　(GR/LDPE).　Based　on　mechanical　property　tests,　ballistic　impact　test　and　finite　element　analysis　(FEA),　the　ballistic　behaviours　and　key　mechanism　of　modified　fabrics　are　revealed.　Experimental　results　show　that　LDPE　or　GR/LDPE　modification　does　not　change　the　tensile　strength　and　Young＇s　modulus　much,　but　it　greatly　improves　the　interyarn　friction　of　fabric.　This　improvement　in　the　interyarn　friction　leads　to　twice　ballistic　limit　velocities　of　pure　aramid　fabric;　the　ballistic　limit　velocities　of　pure,　LDPE　and　GR/LDPE　aramid　fabrics　are　105　m/s,　223　m/s　and　216　m/s,　respectively.　However,　excessive　friction　causes　negative　effects,　which　is　why　GR/LDPE/aramid　fabric　is　weaker　than　LDPE/aramid　fabric.　The　FEA　results　show　that　fabric　motion　and　deformation　are　the　main　ways　to　resist　impact　as　they　absorb　over　85%　of　the　dissipated　kinetic　energy　of　the　projectile.　The　novel　modification　method　could　be　applied　to　the　manufacturing　of　lightweight　and　effective　body　armour.