The new comb-copolymers [polyacetylene–MPEG (polyethylene glycol monomethyl ether)] were synthesized with (nbd)Rh+[η6-C6H5B- (C6H5)3] as catalyst. The copolymers with moderate molecular weights (Mn) (13000-170000) and yields (31.6-47.3%) exhibited higher optical activities compared with chiral monomer, which accorded with the “Chiral Amplification” effect. The optical activity of the copolymers gradually decreased as the amount of MPEG increased. The maximum amounts of MPEG for successful copolymerization and optical activity of copolymers were 40%, 30%, 20%(mol%) as the Mn of MPEG was 350, 750,1900, respectively. The optical activity of copolymers could change at external environmental stimulation, e.g., decreased as methanol content increased.