A series of poly(hexamethylene sebacate) (PHS), with molecular weight in a range of 890-2200, based polyurethanes (PU), were synthesized by solution polymerization with different kinds of isocyanate and chain extender and two kinds of polymerization methods. All the PHS-based PU membranes exhibited selectivity towards styrene during the pervaporation of styrene-ethylbenzene mixtures, and the properties of sorption and pervaporation were related to the composition of the PU membranes. Membranes with a low hard-segment content and by two-stage polymerization method exhibited high permselectivity.