Abstract: For a purpose of verification and optimization of the thermal insulation design of a high speed aircraft, an accurate method is need to complete a simulation of inner heat transfer process caused by outer high speed aero-thermal flow. Therefor a simulation method that can solve outer fluid field and its aero-thermal, structural thermal conduction and inner fluid temperature distribution is studied, where heat transfer methods include conduction, convection, and radiation. The method adopt a structure of two models, two solvers and one transfer file, which constructs a fluid-thermal-structural multiple physical coupled method so as to realize transient temperature simulation and analysis in a inner fluid field which is isolated by solid structure with outer fluid field. In the end, an example is given to verify the whole method, and the results can be used to guide the thermal insulation design of a high speed aircraft.