Nanofiltration　membrane　with　high　water　permeability　and　anti-fouling　nature　is　particularly　needed　to　be　explored　in　dyeing　wastewater　treatment.　Herein,　a　hydrophilic　calcium　carbonate/polyethyleneimine-gallic　acid　(CaCO3/PEI-GA)　loose　NF　membrane　was　prepared　via　a　layer　assembled　in-situ　mineralization　(LAIM)　strategy.　This　strategy　endowed　the　membrane　with　the　following　advantages:　the　formation　an　ultrathin　CaCO3/PEI-GA　selective　layer　with　a　thickness　of　76　nm　and　the　highly　enhanced　surface　hydrophilicity　due　to　in-situ　formation　of　CaCO3　nanoparticles.　As　a　result,　the　prepared　CaCO3/PEI-GA　loose　NF　membrane　showed　154%　higher　water　flux　(48.5　L/(m(2)　h　bar)　vs.　19.1　L/(m(2)　h　bar))　compared　with　the　control　polyethyleneimine-gallic　acid　(PEI-GA)　loose　NF　membrane　for　100　mg/L　Congo　red　(CR)　solution,　with　equivalent　rejection　(99.6%　vs.　99.7%).　Moreover,　this　membrane　also　displayed　outstanding　anti-fouling　ability,　i.e.　flux　recovery　ratio　(FRR)　of　94.9%　for　1000　mg/L　humic　acid　(HA)　solution,　and　excellent　performance　stability　in　separation　of　dye/salt　(CR/NaCl)　aqueous　solution　for　60　h.　The　aforementioned　advantages　of　the　CaCO3/PEI-GA　loose　NF　membrane　indicate　its　promising　application　in　dyeing　wastewater　treatment.