Abstract: The 2-hydroxy-1-naphthalene formaldehyde imine nickel complexes is synthesized from 2-hydroxy-1-naphthalene formaldehyde and o-toluidin,and then bis(substituted-salicylaldimene)Ni(Ⅱ) complexes is prepared from aniline and bis(salicylaldehyde)Ni(Ⅱ), these two complexes can be used as catalyst for propylene dimerization. The complexes were characterized by IR and UV spectrum. The thermal properties of complexes were determined by DSC .The properties of complexes /triphenylphosphine solution system were investigated UV method, and then the plausible formation mechanism of catalytic active site was deduced.