With a view to be able to prepare high performance nanofiltration membranes, we made experiments where NF composite membranes were prepared by interfacial polymerization, using ultrafilitration membrane as substrate and their performances such as water flux, retention of Na2SO4 and PEG 600 were studied. The results show that under an operational pressure of 0.6 MPa, water fluxes of NF-1, NF-2 and NF-3 are 4.1, 6.0 and 26.5 l/m(2)h, respectively, while the retentions of Na2SO4 are 78,94 and 94%, respectively. The chemical composition and the surface image of NF membranes are obtained by using IR and atomic force microscope Also explored are the prospects of their applications in the dyeing industry.