The pervaporation performances of a series of functionalized syndiotactic. poly (styrene-co-4-methylstyrene) (SPSM) membranes for various alcohol mixtures were investigated. The effect of functionalization on the thermal properties and polymer structure of the SPSM membranes were also investigated. The crystallinity of the functionalized SPSM membrane is lower than that of the unfunctionalized SPSM membranes. The water molecules preferentially permeate through the SPSM membranes. Compared with unfunctionalized SPSM membranes, the functionalized SPSM membrane effectively increases the membrane formation performances and the pervaporation performances. The optimun pervaporation performance (a separation factor of 5 10 and permeation rate of 220 g/m(2)h) was obtained by the bromination of SPSM (SPSMBr) membrane with a 90wt% aqueous ethanol solution.