To guarantee high image quality of astronomical observation,high-precision stabilization system is needed for space telescope.The control of Large-Aperture Fast Steering Mirror (LAFSM) is the key for realizing precise image stabilization,whose performance determines the boresight stabilization accuracy of the space telescope.Both Internal Model Control (IMC) and H∞ are employed to design a compound control system, and an analysis is made to its controlling performance.The simulation results show that the controller has strong stability and robustness.