Polymerization of butadiene catalyzed by the fitle catalyst have been investigated. It was found that by adding halides to a tricomponent catalyst

the catalytic activity and the stability of active species of the system will be increased and the molecular weight of the polymer can be regulated. The feeding order of the catalyst components has significant influence on the catalytic activity

UV-Vis spectra of the catalyst indicated that the absorption band at 510 nm is the characteristic band of active species of the catalyst. A possible me-chanism for the interaction between components of the catalyst was suggested.