Graphene　(G)　is　an　excellent　protection　material,　but　suffering　corrosion-promotion　effect　because　of　its　intrinsic　high　electrical-conductivity.　Herein,　a　facile　strategy　is　presented　to　effectively　lower　the　conductivity　of　the　G　by　the　encapsulation　of　insulating　poly(p-phenylenediamine)　(PpPD).　The　obtained　G@PpPD,　which　delivers　an　extremely　low　conductivity　of　3.5×10−7　S　cm-1,　were　then　mixed　with　polyvinyl-butyral　(PVB),　forming　a　compact　composite　coating　that　can　effectively　protect　Q235　steel　from　being　corroded　over　a　very　long　period.　Such　a　superior　anticorrosion　property　can　be　owing　to　the　synergistic　effect　between　impermeable　graphene　and　insulated　PpPD,　which　not　only　hinders　the　diffusion　of　the　corrosive　media,　but　also　inhibits　the　corrosion-promotion　activity　of　the　graphene.　This　effective　strategy　may　provide　valuable　enlightenment　for　the　further　development　of　graphene-based　polymer　anticorrosive　coatings　with　long-lasting　corrosion　resistance.　©　2021　Elsevier　B.V.