A novel zirconium complex bearing bis(phenoxyketimine) ligand (1) bis((3,5-di-tert-butyl-C 6 H 2 -2-O)PhCN(2,4-di-fluoro-C 6 H 3 ))ZrCl 2 (2) was prepared and successfully immobilized on a mesoporous molecular sieve MCM-41 in chemical method. Results of slurry polymerization of ethylene with MCM-41-supported catalyst (MC) indicated that the morphologies of polyethylene obtained differed greatly in heptane and toluene. Homogeneous catalyst 2 exhibited a very high initial activity in ethylene polymerization at room temperature resulting in great viscosity of the system. When immobilized on MCM-41, MC showed a smooth yet highly active kinetic behavior. With MAO as the cocatalyst, the effects of Al/Zr molar ratio and polymerization temperature on catalytic activity and properties of polyethylene obtained were investigated. The results showed that polyethylene obtained with MC possessed higher molecular weight (M n ) and broader molecular weight distribution (M w /M n ) than those formed with its homogeneous counterpart.