Abstract: The oxidation kinetics of A3-3 carbon/carbon composites was investigated at temperatures between 800~1000 C, and the experimental oxygen partial pressure was 21.3kPa.The experiment results showed that the oxidation rate of A3-3 carbon/carbon composites increases suddenly at first and then reaches a steady point. The steady oxidation rate could be expressed as r=119exp(-15613/RT)mg/cm²·h,and is not influenced by its doping elements. Otherwise,the oxidation resistance of A3-3 carbon/carbon composites is mainly determined by the carbon derived from the PF resin.