Over the last years a body of studies has been proposed by several authors to calculate the thermal conductivity of nanofluid, using the molecular dynamics (MD) simulations based on the Green Kubo formalism applying the well-known Lennard-Jones potential. The present work shows the influence of the solid-solid inter-atomic potential type on the thermal conductivity of nanofluids. The effective thermal conductivity obtained from the conventional models is compared with the present simulation, by varying nanoparticles concentrations and the system temperatures. The present results follow considerably the theoretical models integrating the Brownian motion of nanoparticles inside the base fluid. Our mainly findings suggest that the thermal conductivity of (Ar-Cu) nanofluid is influenced by the type of potential used in the simulation. Furthermore introducing Morse potential, which is recommended for metallic's interactions between (Cu-Cu) atoms, enhances significantly the simulation results of nanofluid thermal conductivity and shows a good agreement with the existing literature data. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.