Abstract: The effects of load and voltage on the tribo-electric behaviour of rolling Cu pairs were investigated by the FTM-CF100 tribometer. The mechanism of tribo-electric performance was analyzed by scanning electron microscope and white light interference 3D profilometer. The deformation of the rough contact surface was elevated by the increase of load and applied voltage. Therefore, the contact resistance decreased due to the increase of real contact area and the stability of the dynamic friction coefficient and contact resistance was improved by the smoother surface. The adhesion of Cu occurred more easily on the tribo-electric contact surface probably because of the Joule heat, hence the friction coefficient increased with the applied voltage and was a little higher than that of mechanical rolling contact.