In this research, thin film heterogeneous cation exchange membrane was prepared by interfacial polymerization of polyacrylic acid-co-iron nickel oxide nanoparticles on PVC based substrate. Spectra analysis confirmed graft polymerization conclusively. The SEM images showed that polymerized layer covers the membranes by simple gel network entanglement. Results exhibited that membrane water content was decreased by graft polymerization of PAA/Fe2NiO4 nanoparticles on membrane surface. Membrane potential, transport number and permselectivity all were declined initially by PAA interfacial polymerization in NaCl ionic solution and then began to increase. The membrane transport number and permselectivity showed decreasing trend in bivalent (BaCl2) ionic solution. The sodium flux and permeability were improved sharply by PAA graft polymerization on membrane surface and then decreased slightly by graft polymerization of PAA/Fe2NiO4 nanoparticles. Different behavior was found for barium flux and permeability. Membrane areal electrical resistance was also decreased by introducing interfacial graft polymerization on membrane surface.