A new supported catalytic system of Cp* Zr Cl2/BF3/Al2O3 for ethylenepolymerization was prepared . The preparation conditions such as pretreatment temperature
reaction time and the concentration of added-BF3 were investigated . It was found that thechemicalreaction and physical adsorption occurred between BF and Al2O3. Their frequencywas dependent on the OH concentration at Al2O3 surfaces. Ahigher polymerization activity106~107g PE/mol Zr·h was obtained by using the resultant supported catalyst even at lower [Al]/[Zr]ratios.