Membrane technology has been developed significantly because it could be applicated on several fields. Therefore, in this study we report the manufactures of cellulose acetate nanofiltration membranes. The membranes were fabricated from dope solution consisting of cellulose acetate, poly ethylene glykol (PEG), distilled water, and acetone using a simple dry/wet phase inversion process. Production condition used included evaporation times of 10, 15, and 25 seconds, PEG addition of 2.5%; 3.5%; and 5%, with and without non-solvent addition of 1% distilled water in order to fabricate a high performance nanofiltration membrane. The mambranes performance that are based on percentage of rejection of barackish water and multivalent ion Ca2+, flux and mechanical strength of membrane. Generally, the percentage rejection and mechanical strength were found to increase and the flux were decrease with increasing of eveporation times. In the other side, the percentage of rejection, flux and mechanical were found to increase with increasing PEG addition. The percentage of rejection and mechanical strength were found the best in membranes with addition non-solvent of 1% distilled water, but the fluxes were the least. An optimimum membranes performance were found at compotition of dope solution composition consisting of 23% CA, 5% PEG, 25 seconds evaporation times and 1% distilled water
