Abstract: In this work, two kinds of extruder heads were designed to produce different processing force fields. The morphology and electrical and thermal conductivity of polypropylene (PP)/graphene nanoplatelets (GNPs) nanocomposites were investigated, and the effect of distribution of GNPs in the PP matrix on the performance of the nanocomposites was also studied. The results indicated that the tensile force field generated by the convergent flow channel had a peeling and dispersing effect on GNPs and therefore reduced the agglomeration of GNPs. The chaotic mixing force field generated by use of a static mixer further improved the dispersion uniformity of GNPs in the matrix, which facilitated the construction of an electrically conductive and thermally conductive network. As a result, the electrical and thermal conductivity of the nanocomposites was improved. For the nanocomposites containing 6 wt% of GNPs prepared by using a static mixer in the extrusion head, the conductivity was improved by 5 orders of magnitude and the thermal conductivity was improved by 24.1 % compared to the nanocomposites prepared without a static mixer.