Rare-earth acetates were used to catalyze the copolymerization reaction of carbon monoxide and styrene. Cupric acetate, 1,10-phenanthroline, p-toluenesulfonic acid, and 1,4-benzoquinone were also added to the catalyst system. The structures of the copolymers obtained were characterized with IR, H-1 NMR, C-13 NMR, wide-angle X-ray diffraction, and elemental analysis methods. The relationship between the catalytic activity and the catalyst composition was studied in detail.