Abstract: The copolymer of carbon monoxide with styrene is of great interest, because as a monomer, carbon monoxide is particularly plentiful and inexpensive, the presence of the carbonyl groups in the backbone makes the copolymer photodegradable and the copolymer can be chemically modified to become excellent starting materials for other classes of functional polymers. Copolymerization of carbon monoxide/styrene was catalyzed by a catalytic system comprising palladium acetate as precursor. Kinetic study showed that copolymerization underwent a short transition period, in which the real active species were produced. The activity and life of the catalytic system are influenced by a number factors, such as the structure of ligands and their amounts. The mechanism of initiation and the catalytic cycle for the copolymerization were studied. Additionally, through parallel experiments, we concluded that different ligands and their amounts influenced the coordinating structure of the species as well as their catalytic activity and life.