Abstract: C/C-C_u composites were fabricated by infiltrating molten C_u alloy into C/C preforms The tribological behavior of the composite block against C_u ring was evaluated using an MM -2000 friction and wear tester The influences of externally applied electrical factors on tribological behavior of the composite were investigated , and their interacting mechanism was analyzed The results showed that the direction of current determined the existence or non -existence of wear debris layer , and had much impact on friction coefficient The friction coefficient and wear rate of the composite under positive direction were higher than that under negative direction Current intensity had a significant influence on wear rate of the composite With increasing current intensity , the wear rate increased and wear mechanism changed from ploughing wear to adhesive wear The friction coefficient increased firstly and then dropped with the rising current intensity