N,O-carboxymethyl　chitosan　(NOCC)　composite　nanofiltration　membranes　crosslinked　by　ECH　were　developed　using　a　method　of　coating　and　crosslinking,　where　an　epichlorohydrin/ethanol　96.7%　(0.067　M　KOH)　solution　was　used　as　the　crosslinking　agent.　The　structure　and　the　morphology　of　the　resulting　membrane　were　characterized　by　attenuated　total　reflection　infrared　spectroscopy　(ATR-IR)　and　environmental　scanning　electron　microscopy　(ESEM).　The　effects　of　preparation　conditions　on　the　rejection　performance　of　the　resulting　composite　membrane　were　also　investigated.　At　20　degrees　C　and　0.40　MPa　the　rejections　of　the　resulting　membrane　to　Na2SO4　and　NaCl　solutions　(1000　mg　L-1)　were　90.4%　and　27.4%,　respectively,　and　the　permeate　fluxes　were　7.9,　and　10.8　kg　m(-2)　h(-1),　respectively.　The　rejections　of　this　kind　of　NOCC/PSF　composite　NF　membrane　to　the　inorganic　electrolyte　solutions　decreased　in　the　order　of　Na2SO4,　NaCl,　MgSO4,　and　MgCl2.