A nickel (Ⅱ) catalyst of diphosphinoamine complex ［N

N-bis(diphenylphosphino)-p-methoxyaniline nickel(Ⅱ) dichloride］was synthesized.Norbornene polymerization catalyzed by this nickel(Ⅱ) complex (PNP-Ni)/MAO system was investigated.The influence of reaction parameters (temperature

Al/Ni mole ratio

and catalyst concentration) on polymerization of norbornene was evaluated.Results showed that the catalytic system displayed high catalytic efficiency with 105g PNBE/(mol Ni) magnitude order.The Mw of polynorbornene is higher than 1×106g·mol-1 and the MWD is narrow（Mw/Mn＜2）.Also

the PNBE is of excellent heat-resistant property and the Tg is higher than 300℃

and it is soluble in cyclohexane

chlorobenzene

and so on.According to 1H and 13C-NMR spectra

the polymerization mechanism is vinyl-addition type polymerization

and the contents of stereo-triad of PNBE are (mm)= 53％

(mr)=39%

(rr)=8%.