An aerodynamic design optimization method is presented which is based on dynamic boundary control. This method is according to the idea of controlling the boundary of transforming object. By solving the unsteady flow governing equations, we obtain the sensitivity derivatives of object function to design variables. The design variables are changed to increase the object function value until the optimization result is obtained using sensitivity derivatives. Since solving steady governing equations or adjoint equations is not necessary, the optimization procedure is simplified and the method is suitable for many cases. This method is applied to two dimensional airfoil design optimization to demonstrate its efficiency and validity.