In this work, the preparation and characterization of metallocene-catalyzed polyethylene (PE)/kaolin composites were presented. The composites was prepared by the so-called polymerization-filling method in which the PE matrix was formed directly on the kaolin surface by ethylene polymerization with the prefixed Cp2ZrCl2/methylaluminoxane (MAO) catalyst system on the kaolin surface. SEM, FTIR, and DMA were carried out to characterize the composites. The experimental results showed the new composites had homogeneous distribution of kaolin particles in the PE matrix and strong interfacial interaction between the PE matrix and kaolin particles, At the molecular level, the interfacial interaction caused the decrease of the mobility of PE molecular chains. In addition rheological testing showed that the introduction of kaolin by polymerization filling could improve the rheological behavior of prepared composites. The relationship between the rheological behaviors and the interfacial conditions were discussed.