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Polyamide (PA) hollow fibre composite nano-filtration (NF) membranes with a coffee-ring structure and beneficial properties were prepared by adding graphene oxide (GO) into the interfacial polymerization process.The presentation of the coffee-ring structure was attributed to the heterogeneous,finely dispersed multiphase reaction system and the “coffee-stain” effect of the GO solution.When the piperazine concentration was 0.4 wt-％,the trimesoyl chloride concentration was 0.3 wt-％,and the GO concentration was 0.025 wt-％,the prepared NF membranes showed the best separation properties.The permeate flux was 76 L· m-2· h-1,and the rejection rate for MgSO4 was 98.6％ at 0.4 MPa.Scanning electron microscopy,atomic force microscopy,and attenuated total reflectance-Fourier transform infrared spectroscopy were used to characterize the chemical structure and morphology of the PA/GO NF membrane.The results showed that GO was successfully entrapped into the PA functional layer.Under neutral operating conditions,the PA/GO membrane showed typical negatively charged NF membrane separation characteristics,and the rejection rate decreased in the order of Na2SO4 ＞ MgSO4 ＞ MgCl2 ＞NaCl.The PA/GO NF membrane showed better antifouling performance than the PA membrane.