The ［OSSO］-type bis(phenolate) titanium complex (［OSSO］TiCl

2

) was supported by MgCl

2

/AlEt

n

(OEt)

3-n

and then used to efficiently promote the polymerization of ethylene under the activation of the cheap diethylaluminum chloride (AlEt

2

Cl). The resulted polymer was a long chain branched polyethylene. The influences of the preparation technology of support

triethyl aluminum modifying the adduct of MgCl

2

and ethyl alcohol (EtOH) (MgCl

2

/AlEt

n

(OEt)

3-n

)

and the polymerization conditions including polymerization temperature

ethylene press and Al（in AlEt2Cl）∶Ti on the polymerization behavior and the polymer structure were explored. The result indicated that the supported catalyst could more actively promote the polymerization of ethylene than the homogeneous catalyst with the highest activity of 10

6

g

(PE)

/(mol

(Ti)

·h)

which was hundredfold of the homogeneous catalyst. The analysis of the

13

C nuclear magnetic resonance spectroscopy  confirmed that the obtained polyethylene catalyzed by the supported catalyst was the long chain branched polyethylene with a branch number of 15 and a long branched chain content of 60.2%. The analysis of differential scanning calorimetry shows that the melting temperature of the branched polyethylene was 126 ℃. The kinetics of the ethylene polymerization was steady.