Branched polyethylene from ethylene as single monomer was prepared by the tandem catalyst system of {2-[2-Me C6H4 =(Me)]2C5H3N}FeCl2(1) and {2

6-[1-(2

6-Me2-4-Br-C6H4N=(Me)]2C5H3N} FeCl2 (2) activated with methylaluminoxane (MAO)．The products of polymerization were characterized by DSC

GPC and 13C-NMR. The results revealed that the copolymer produced by in situ copolymerization of ethylene was a mixture of branched polyethylene and α-olefin．The content of α-olefin in the mixture was increased with increasing the molar ratio of catalysts 1／2．The MWD paramelers of polyethylene and copolymer were 28.6 and 7.9

respectirely. 13C- NMR spectra showed that there were ethyl groups

butyl groups and long chain alkyl groups in the copolymer．The average degree of branching of such branched polyethylene was less than 5C／1000C．