The composite nanofiltration membranes were prepared via interfacial polymerization of tetraethylenepentamine (TEPA) and 1,3,5-benzenetricarbonyl trichloride (TMC). The improved performance of the composite nanofiltratiom membranes by adding calcium chloride in aqueous phase during the interfacial polymerization was verified in terms of pure water permeability, rejection of different solutes including dyes and inorganic salts and chlorine resistance. The results showed that the pure water permeability of composite nanofiltration membranes would acquire a remarkable increase with a slight decrease in solute rejections under the optimized addition of CaCl2. The addition of CaCl2 also dramatically enhanced the chloride resistance of composite nanofiltration membranes in comparison with the control membranes prepared without CaCl2 added. Therefore, inorganic salts like CaCl2 could be considered as a potential additive to enhance the performance of composite nanofiltration membranes. (C) 2013 Elsevier B.V. All rights reserved.