Oxidation damage is one of the main factors affecting the life of C/SiC composite nozzle used in rocket engines. To accurately predict the oxidation damage of C/SiC composite nozzle, we explored the oxidation behavior of the tubular C/SiC composites which had a similar shape to nozzle. Evolution of their composition, structure, and mechanical properties was investigated at different temperatures ranging from 900 to 1300 ℃. The results showed that the tubular C/SiC composites exhibited diffusion-controlled oxidation characteristics under the high-temperature environment. Their mass and residual strength decreased as a power function with time, and decline rate was positively correlated with temperature. Moreover, based on the theory of oxidation kinetics and mass transfer, a macro-meso oxidation model was established to simulate the oxidation process of tubular C/SiC composites in high-temperature environment to timely predict the evolution of their mass and residual strength. Consequentely, all the predicted results of the model fitted well with the experimental data. Our investigation consolidate that this macro-meso oxidation model is powerfull to predict the oxidation behavior and the life-span of C/SiC composite nozzle.