An in-situ supporting method was applied to a new metallocene catalyst with a bulky structure, [(CH2)5(C5H4)2][(C9H7)ZrCl2]2, and other commercial metallocene catalysts; the polymerization characteristics of the supported catalysts were studied. Polyethylene obtained from the in-situ supported [(CH2)5(C5H4)2][(C9H7)ZrCl2]2/TMA catalyst showed a higher yield, a better morphology, a lower average molecular weight, and a broader molecular weight distribution than the catalyst supported by a traditional method. In-situ supported catalysts also showed that catalytic activities and polymer properties depended on the type of the cocatalyst used. When an alkyl aluminum was used as a cocatalyst, a lower activity was observed than the case of modified methylaluminoxan (MMAO), but it showed the characteristics similar to a heterogeneous catalyst. Trimethyl aluminum (TMA) showed the highest activity in polymerization among other alkyl aluminums, but excess addition of TMA resulted in a lower average molecular weight and activity by inducing deactivation of metallocenes of chain transfer. An in-situ supported rac-Et(Ind)2ZrCl2 catalyst produced the polypropylene with a higher melting temperature and a lower average molecular weight than a homogeneous system.