Novel non-metallocene complexes are synthesized in which titanium is coordinated with acetylnaphthoxy ligand with a formula [O

O]n TiCl4-n. Their composition and structure are characterized by element analysis and IR spectroscopy．The results suggest that the ring structure is formed by the combination of two oxygen atoms in the acetylnaphthoxy ligand [O

O] and titanium atom

while n is 1 or 2．The catalysts are applied in ethylene polymerization．It is found that the catalytic activity of the catalysts for homogenous ethylene polymerization is not high with MAO as co-catalyst due to the association phenomena of the complexes．The molecular weight distribution of polyethylene obtained in homogenous polymerization is wide．The results indicate that the complexes may be “multi-site” catalysts in homogenous polymerization．The catalytic activities of the non-metallocene complex reach 106 gPE／(molTi·h)

when it is supported by MgCl2．The amount of MAO can be decreased or replaced by alkyaluminum．In heterogeneous catalysis

the molecular weight of polyethylene is higher and the molecular weight distribution is narrower than those in homogenous catalysis．Through the study of XPS

the electron reduction of titanium and the draw-electron effect of magnesium are confirmed

which will favor the coordination of olefins．