Abstract: A hierachical solution process is used to analyze the flutter of a fin in hypersonic flow. A reduced-order model based on Volterra series is employed to establish an unsteady aerodynamic state space model. A load interpolation transfer method in parametric space is used to transfer data between aerodynamic meshes and structural meshes. A finite model for thermal-vibration analysis is obtained with the uncoupled thermal-structure analysis method. Combining the unsteady aerodynamic model with the structural finite model, an aeroelastic model is established. At last, this aeroelastic model is applied to predict the flutter of a fin with root fixed in hypersonic flow. The results show that, taking the aerodynamic heating into account, the critical flutter speed decreases sharply due to the declination of the first bend and torsion frequencies.