Abstract: The effect of braking pressure on the tribological properties of carbon/carbon composites manufactured by isothermal and thermalgradient chemical vapor depositions was investigated by optical microscopy, scanning electron microscopy and a laboratory dynamometer. Results indicate that the coefficient of friction decreases and weight loss increases with braking pressure from 0.35MPa to 1.82MPa. The oxidation erosion of rough laminar is lower than that of smooth laminar because of its better microstructure. The wear debris of rough laminar can be easily deformed plastically, leading to a thin and uniform film on the friction surface that reduces the oxidation erosion.