The comprehensive performance of graphite and additives filled high-density polyethylene (HDPE) composites is studied in this article. Four graphites with different particle diameters are used as conductive fillers in HDPE/graphite. Plasticizer, nucleator, and certain particle diameter graphite are employed to prepare HDPE composite. The behavior of crystallization and the distribution of graphite are also studied by means of SEM. An orthogonal design experiment is taken to optimize the content of the filler. The experimental results indicate that the positive temperature coefficient (PTC) effect is related to the particle diameter of graphite. And the bending strength of HDPE/graphite composite with the plasticizer and nucleator is two times less than that of HDPE-graphite blends. Meanwhile, the high PTC intensity (the ratio of peak resistivity to room temperature resistivity) is also preserved. An excellent comprehensive performance conductive composite is prepared. (C) 2007 Wiley Periodicals, Inc.