Abstract: The effects of current,friction speed and load on wear rate and friction coefficient of C/C composites were investigated under air/nitrogen atmospheres,the morphology and component of worn surface were observed and analyzed. The results show that the wear rate and friction coefficient increase with the increase of current and friction speed,the friction coefficient in nitrogen atmosphere is higher than in air atmosphere,and the wear rate in nitrogen atmosphere is lower than in air atmosphere. The oxidation of carbon materials in air atmosphere increase the wear and result in the higher wear rate,and the oxide film formed on friction material surface makes the lower friction coefficient.