Abstract: In order to support the regenerative cooling structure design and experiment of scramjet, an analytical model of unsteady heat exchange is constructed. The calculated and experimentally measured thermal equilibrium times under water cooling condition are compared. The calculated irregular temperature increasing time is obtained using the analytical model and compared with experimental values. It is found that the thermal equilibrium time can be decreased if the scramjet is preheated to 800 K before test. The research shows that the analytical model is applicable to heat transfer analysis of the regenerative cooling scramjet.