Abstract: An aerothermoelastic analysis of a hypersonic all-movable control surface, in which the effects of the axis and the gap were considered, was carried out based on the hierarchical solution process. The CFD (Computational Fluid Dynamics) method was firstly used to solve the N-S (Navier-Stokes) equations and get the thermal environment around the control surface. Then the wall heat flux was calculated based on the surrounding temperature and the wall temperature. The heat conduction was solved using Fourier's law to obtain the structural temperature distribution. In addition, the structural inherent characteristics considering thermal stress and material degradation were analyzed. The unsteady aerodynamic forces were calculated through local flow piston theory based on CFD. Lastly the flutter was analyzed by state space method. The results show that changes of natural frequencies and pitches between the bending frequencies and the torsion frequencies due to the aerodynamic heating result in changes of the flutter speeds and the flutter frequencies; with heat conduction going on, the natural frequencies and the flutter frequencies become unchanged after a rapid decrease, and the pitches increase slowly after a rapid decrease; the natural frequencies and the flutter frequencies as well as the flutter speeds firstly decrease and then increase with time when only thermal stress takes effect; the axis and the gap can lead to decrease in the natural frequencies, the flutter frequencies and the flutter speeds and the maximum reduction reaches to 6%.