This book presents selected papers from the 6th China National Congress on Thermal Stress. The Congress was hosted by the Chinese Society of Theoretical and Applied Mechanics and Northwestern Polytechnical University and held on 18~20 April, 2025 in Xi'an, China. The high-speed flight technology of aerospace vehicles will significantly enhance humanity's capabilities to explore and utilize outer space. The new generation of hypersonic vehicles is evolving towards higher altitudes, greater speeds, and longer endurance. High energy density applications within the cabin are becoming more common. Combined with severe aerodynamic heating and substantial waste heat from engine combustion, these vehicles face a much more severe thermal environment. Meanwhile, there is a strong coupling effect between the thermal response of the internal structure of the vehicle and the aerodynamic heating phenomenon of the external flow field, with distinct characteristics of non-steady-state, non-linearity, and multi-scale behaviour. The coupling mechanism still requires continuous exploration. In addition, railway system is continuously developing towards higher speeds and heavier loads, bringing about frictional heat issues. Moreover, thermal fatigue problems in nuclear power equipment, steam turbine rotors, and pipelines also need to be addressed urgently.