Abstract: Based on the simply analysis of damage mechanism for C/SiC composites and its performance evolution of acoustic emission(AE) during tensile test at room temperature, an analytical research on the AE characterization for one C/SiC thermal structure during static strength experiment at room temperature has been conducted, aimed at the complex characteristics caused by the component assembly design for it. The sort characters of AE parameter were given. The damage evolution patterns were given according to the AE regulation during experimental loading. By the comparison with AE parameter of C/SiC composites, the remaining value was judged between experimental loading to the ultimate damage loading for the thermal structure. So, the AE measure was extended to large C/SiC thermal structure from the research at material level.