Abstract: Four extraction agents, i.e. di-(2-ethylhexyl)-phosphoric acid (P204), 2-ethylhexyl phosphoric acid mono-(2-ethylhexyl) ester (P507), tributyl phosphate (TBP) and 1-octanol (NOOH), were used to synthesize oxo-vanadium complexes by extraction method, and the synthesized complexes were used as catalysts for ethylene polymerization. These four complexes were characterized by elemental analysis, FT-IR and the structures of the polymerization products were characterized by GPC, DSC and 13C NMR. Test results showed that under atmospheric pressure, activated by Et3Al2Cl3, the catalytic activities for ethylene homopolymerization of these catalysts were in the range of 23—57 kg/(mol?h)，and the obtained polymers were linear high density polyethylene, with Mν = 4.8—9.5 × 104，PDI = 4.5, Tm = 136—138 °C.

Key words: oxo-vanadium complex, extraction, ethylene, polymerization