Abstract: In this paper, the integrated optimal design methodology of mechanical and control system is discussed with regard to the performance requirement and configuration of flexible manipulator. In terms of percent overshoot σ_p and the settling time t_s, the viable region of poles of the closed-loop transfer function is decided. Then, by the combination of dynamics of flexible structure and control theory, the optimum model including structure and control parameters is proposed. Finally, the objective function, which contains the moment of inertia and the control effort of system, is optimized.