Abstract: The constrained optimum aerodynamic design method isdeveloped in the framework of control theory in order to implement allthe constraints implicitly and automatically. With the constrainedadjoint method developed in this paper , only the boundary condition ofadjoint equations and the gradient computation need to be modifiedslightly as compared with Jameson's original unconstrained formula,other terms are maintained thesame. It turns out that the control theory basedoptimization method is very suitable not only for the designs with a largenumber of design variables but also for the designs with constraints.