Development of composite membrane using organic polymer and inorganic nanoparticles is an emerging field of water purification process. Here we report the preparation, characterization and performance of a novel composite polymeric membrane prepared using composite of spray dried silica granule and polysulfone. We investigate the structure and performance of the membranes prepared using N-methyl-2-pyrrolidone or N,N-dimethyl formamide as solvent for the composite material. Such polymer-nanocomposite membrane shows significant enhancement of water permeability without sacrificing for the separation performance. In order to establish the structure-function correlation, we probed the mesoscopic structure of polymer casting solution and final membranes using small-angle scattering, atomic force microscopy and contact angle measurements. We put forward a plausible mechanism in support of the enhanced performance of the composite membranes. (C) 2013 Elsevier B.V. All rights reserved.