Abstract: Propylene-butadiene copolymerizations with TiCl₄/MgCl₂/AlEt₃and TiCl₄/ MgCl₃/AlEt₃/EB catalyst were studied respectively. It was found that copolymer obtained by the first catalyst give more butadiene content and lower reduced viscosity than that obtained by second one. The copolymerization products have been confirmed to be copolymer containing long propylene-propylene sequence and butadiene-butadiene sequence by solvent extraction, IR, ¹³CNMR, X-ray, and DTA. Butadiene unit in copolymers is exclusively in trans-1,4 structure.