Abstract: High mach number flight will create much higher dynamic pressures and temperatures compared to conventional flight vehicles. The thermal-acoustic traveling-wave tube is a testing equipment for structural strength assessment under acoustic and thermal combined environment. As the flight speed increases, the magnitude of thermal-acoustic environment test correspondingly increases and presents challenges to the design of the thermal-acoustic traveling wave tube itself. In this paper, the thermal-acoustic simulation analysis method of thermal-acoustic traveling wave tube is studied, which uses large-size radiation to heat the big specimen and combines with high-noise environment, so as to provide a basis for structural design. Firstly, a temperature field simulation model of traveling wave tube with external radiation heating is established to evaluate the distribution characteristics of internal temperature field under heating conditions. According to the temperature field distribution within the traveling wave tube, a simulation analysis model of the traveling-wave tube sound field in consideration of the effect of the temperature is further established, and the simulated analysis is carried out on the sound field characteristics under the heating state. Finally, some reasonable suggestions for the structure design of large external radiation-heated thermal-acoustic traveling-wave tube are put forward based on the analysis results.