This paper focuses on the numerical simulation of the polypropylene/multi-walled carbon nanotubes (PP/ MWCNT) flow into a twin-screw mixer, during the mixing phase. The PP/MWCNT behavior obeys an innovating Carreau law enriched temperature built on the rheological properties carried out previously. The polypropylene was mixed with different MWCNTs contents (1, 2, 4 and 8 wt.% of MWCNT content) and the rheological tests were performed at shear rate ranges from 10 À1 to 2 Â 10 4 s À1 at four temperatures (180, 200, 220 and 240 °C). Thus the effects of the temperature and the MWCNTs content on the rheological properties of the PP/MWCNT composites were investigated. The finite element (FEM) analysis of the PP/MWCNT flow allows to compute the velocity, the shear rate and the temperature during the mixing phase period. A good agreement between the experimental measured torque on the screw and the calculated one is shown. Therefore, one can consider that the physical flow is generally well described, awaiting a numerical simulation of the PP/MWCNT mixing phase.