Abstract: ZM complex catalyst was prepared by impregnating metallocene catalyst on supported Ziegler-Natta catalyst, its catalytic performance in ethylene polymerization toward bimodal polyethylene in a single reactor was investigated. The influence of the amount of metallocene, polymerization temperature, the amount of co-catalyst and 1-hexene on the catalytic activity was studied. The complex catalyst exhibits high catalytic activity for ethylene polymerization, and the MI values of the polymers are obviously relevant to the polymerization temperature, the mol ratio of Al/M and 1-hexene content in feed. The structure and properties of the obtained polymers were characterized by GPC and FT-IR, which revealed that the polymers featured bimodal distribution with MWD at the range of 18 to 155, and the incorporation of 1-hexene within the polymer chain increased with the increase of the co-monomer content in feed.