The catalytic system of[2-(2-benzimidazolyl)-6-((1-arylirninoethyl)pyridyl)]nickel chloride/MAO (methylalu-minoxane)was found to be good active for vinyl polymerization of norbornene and provided polymers with relative narrow molecular distributions.Various reaction parameters,such as the ratios of nickel precursor to MAO or monomer norbornene,and the nature of the ligands in complexes were carefully investigated to realize their effects on the catalytic activities,polymer molecular weight and molecular weight distributions.