A new three-component catalytic system, PdCl2/bipy/M(CF3SO3)(n), was studied for copolymerization of styrene with CO to prepare alternating polyketone (PK). It is found that the PdCl2/bipy/CF3SO3H catalytic system had a very low catalytic activity for copolymerization of CO with styrene, but when M(CF3SO3)(n) was introduced instead of CF3SO3H, the PdCl2/bipy/M(CF3SO3)(n), catalytic system exhibited high activity. The copolymer was characterized by elemental analysis, FTIR, H-1 NMR, DSC and TGA. The results indicated that the copolymer is a linear alternating copolymer of carbon monoxide and styrene with glass transition temperature, melting point, and decomposition temperature of 275. 350, and 400degreesC, respectively. The effects of M(CF3SO3)(n), ligands, p-benzoquinone/PdCl2 ratio, solvents, and reaction temperatures on the reaction have been discussed in detail. The results showed that this novel catalytic system exhibited high activity, especially when Cu(CF3SO3)(2) was used. The corresponding productivity was 20,000 gPK/molPd h when the reaction was carried out at 338 K for 4 h under 3.0 MPa of CO. (C) 2004 Published by Elsevier B.V..