The rheological and electrical percolation of single-walled carbon nanotubes on a thermoplastic-elastomer based on polypropylene/ethylene-propylene-diene was investigated. Polypropylene-grafted maleic anhydride was used to improve the nanotube dispersion. The shear stress and viscosity decreased with increasing temperature from 200 to 220°C. The flow activation energy for the nanocomposites increased with increasing nanotube content. The morphology and degree of dispersion of the nanotubes in the thermoplastic-elastomer matrix were investigated using SEM. The obtained rheological and electrical properties of the nanocomposites indicate that they were affected by the nanotube-nanotube network structure, which was related to the morphological behavior of nanotubes uniform dispersion.