Removal and enrichment of chlorinated hydrocarbons, such as 1, 1, 2-trichloroethane, TCE, trichloroethylene, TCET, and tetrachloroethylene, TECET, from their diluted aqueous solutions by pervaporation were investigated. As novel membranes with high permselectivity for those solvents, copolymers composed of (trimethylsilyl) methyl methacrylate, TMSMMA, which forms a glassy polymer, and n-butyl acrylate, n-BA, which forms rubbery polymer, were synthesized by radical polymerization. The characterization of copolymers was carried out by FT-IR, 1HNMR, WAXD and DSC. The film formation of the copolymers was better. The effect of molar ratio of TMSMMA/ n-BA on the flux of TCE and the separation factor, α (TCE/water) was clarified. The glass transition temperatures of the copolymers decreased with the increase of n-BA content, which gave the high segmental mobility and thus high diffusivity. The copolymeric membrane containing about 70 mol% of n-BA showed the highest separation factor, 600-1000, for TCE. The high permselectivity for the chlorinated hydrocarbons by the copolymeric membranes was mainly attributed to high partition coefficient for the chlorinated hydrocarbons.