Due to coupling of oxidation damage and mechanical damage,failure mechanism of C/C composites is complex under high-temperature and oxidation environment.In this paper,establishment of cumulative damage analysis method is based on coupling of oxidation damage and mechanical damage.Based on this method,high-temperature and oxidation damage model of C/C composites is established: Initial damage criterion and degradation mode of stiffness in mechanical damage model are modified by oxidation state parameter;Diffusion coefficient of oxygen in oxidation damage model is modified by mechanical damage parameter.Through joint simulation of multiple physical fields of MATLAB and ABAQUS,oxidation damage and mechanical properties of C/C composites under high-temperature and oxidation environment are studied,which has a certain reference significance for structural failure prediction of C/C composites.