The dodecanethiol-modified molybdenum disulfide (OMoS2) was used as template to form a layered OMoS2eMgCl2-supported ZieglereNatta catalyst via a co-agglomeration method. The effects of OMoS2 on the catalyst morphology and ethylene polymerization behavior were examined. The resultant polyethylene (PE)/OMoS2 nanocomposites mirrored the catalyst morphology, and the OMoS2 fillers were well dispersed in the PE matrix. In addition, the thermal stability and mechanical properties of PE were significantly enhanced by the introduction of very small amounts of OMoS2 filler. This enhancement resulted from the good dispersion and interface adhesion of OMoS2 and the PE matrix. Thus, this work proposes a new method for the production of high-performance PE.