Membrane　fouling　is　a　persistent　challenge　that　hinders　the　widespread　application　of　membrane　technology　for　water　treatment.　This　study　introduced　an　innovative　layer-by-layer-assembly　approach　(LBL),　i.e.,　chitosan　(Cs),　β-cyclodextrin　(β-CD),　glycidyl　trimethyl　ammonium　chloride　(GTAC),　to　modify　the　semi-aromatic　polyamide　nanofiltration　membrane　to　enhance　the　separation　performance　and　fouling　resistance.　The　results　show　that　the　LBL　surface　coating,　i.e.,　amino　group　in　Cs　and/or　hydroxyl　group　in　β-CD　reacted　with　the　unhydrolyzed　acyl　chloride　group　in　TMC　and/or　epoxy　group　in　GTAC,　partially　neutralized　the　negatively　charged　membrane　surface　with　enhanced　hydrophilicity.　The　modified　membrane　(named　as　PTCBG)　was　on　par　with　or　even　better　than　the　leading　commercial　NF270　membrane　in　terms　of　permeability　and　selectivity　(A　value:　13.1–13.7　vs.　14.2–14.3　L·m−2·h−1·bar−1;　A/B　value:　9.2–46.9　vs.　3.1–8.8　bar-1,　for　rejection　tests　of　typical　divalent　salts　including　CaCl2,　MgCl2　and　MgSO4).　The　flux　decline　rate　(FDR)　decreased　significantly　from　89%　for　virgin　membrane　to　29%　for　PTCBG　membrane　using　dodecyl　trimethyl　ammonium　bromide　(DTAB)　as　a　model　foulant.　The　corresponding　flux　recovery　rate　(FRR)　was　102%.　It　indicates　the　enhanced　reversible　anti-organic　fouling　property,　which　is　attributed　to　the　weakened　hydrophobic　and　electrostatic　attraction.　The　antibacterial　rate　of　PTCBG　relative　to　virgin　membrane　was　75%　and　68%　for　Escherichia　coli　(E.　coli)　and　Staphylococcus　aureus　(S.　aureus).　The　FDR　of　PTCBG　membrane　exposed　to　E.　coli　and　S.　aureus　was　20%　and　51%,　much　lower　than　35%　and　65%　for　virgin　one.　It　consistently　reflected　the　enhanced　biofouling　resistance　for　PTCBG　membrane,　as　a　result　of　combined　effects　of　weak　adsorption　and　strong　sterilization　on　bacteria,　attributed　to　quaternary　ammonium　introduced　by　GTAC.　This　study　provides　an　innovative　and　straight-forward　strategy　to　fabricate　polyamide　membranes　with　good　permeability/selectivity　and　excellent　fouling　resistance.　©　2025　Elsevier　B.V.