Graphene　(G)　is　regarded　as　a　tremendous　potential　corrosion　protection　material　owing　to　its　perfect　impermeability.　However,　the　tendency　of　graphene　nanosheets　to　agglomerate　and　the　corrosion-promotion　effect　brought　by　its　native　high　electrical　conductivity　seriously　affect　its　anti-corrosion　application.　In　this　paper,　high-energy　ball　milling　was　used　to　prepare　graphene　with　excellent　impermeability.　Then,　insulating　poly(m-phenylenediamine)　encapsulated　graphene　(G@PmPD,　conductivity　of　1.2　10-7　S　cm-1)　was　prepared　through　non-covalent　π-π　interaction.　The　resulting　amino-rich　G@PmPD　exhibits　stable　dispersibility　and　excellent　compatibility　in　organic　solvents　and　polymer　matrix.　Embedding　0.5　wt%　of　G@PmPD　into　the　epoxy　matrix,　and　the　composite　coating　can　effectively　protect　the　steel　substrate　for　up　to　60　d.　This　superior　corrosion　resistance　is　attributed　to　the　impermeability　inherited　by　G@PmPD　and　the　compactness　improved　by　the　cross-linking　of　G@PmPD　and　EP.　Especially　in　the　damaged　state,　the　composite　coating　embedded　with　low　conductivity　G@PmPD　triumphantly　eliminated　graphene＇s　corrosion-promotion　effect.　This　study　provides　promising　inspiration　for　the　application　of　graphene　in　anti-corrosion　field.　©　2021　IOP　Publishing　Ltd.