In　this　work,　a　polyamide　membrane　was　first　prepared　via　in　situ　introduction　of　a　surface-initiated　atom　transfer　radical　polymerization　(SI-ATRP)　initiator　in　interfacial　polymerization.　Then,　a　zwitterionic　membrane　was　obtained　by　SI-ATRP　grafting　of　sulfobetaine　methacrylate　on　a　polyamide　membrane.　The　prepared　membranes　were　characterized　by　Fourier　transform　infrared　spectroscopy,　X-ray　photoelectron　spectroscopy,　and　atomic　force　microscopy,　indicating　the　successful　grafting　of　zwitterions　on　polyamide　membranes.　Pure　water　permeability　of　the　optimized　zwitterionic　membrane　was　up　to　16.8　L　m(-2)　h(-1)　bar(-1),　2.9　times　as　high　as　that　of　the　polyamide　membrane　with　similar　Na2SO4　rejection.　The　NaCl　rejection　of　the　membrane　after　grafting　for　1　h　was　only　17.2%,　much　lower　than　that　with　a　polyamide　membrane,　which　was　sought　for　separation　of　monovalent　salts/neutral　organics.　The　membrane　also　showed　excellent　antifouling　properties　when　three　categories　of　usual　pollutants　were　chosen　as　feed　solution.　The　one-step　SI-ATRP　method　for　preparing　zwitterionic　membranes　with　high　permeability　was　facile　and　convenient,　which　has　promising　applications　in　desalination　and　food　separation　processes.