Abstract: A simple adaptive control algorithm is applied to the design of a reconfigurable flight control system(FCS) in the case of aircraft control surface loss-of-effectiveness failures.When the simple adaptive control is employed,the condition of almost strictly positive realness(ASPR) of closed-loop system must be satisfied,especially when different damages occur in the control surface.A parallel feedforward compensator is obtained by solving the feasibility problem of linear matrix inequalities,and the stability of the closed-loop system and the almost strictly positive realness of the augmented system are guaranteed.The proposed scheme is applied to the reconfigurable design of the flight control system with the help of the lateral flight control system model of an aircraft.The simulation results show that the presented method can not only be suitable for the flight control system in normal flight conditions,but also has strong adaptive capability for the control surface damages.The proposed adaptive controller exhibits improved tracking and reconfigurable control performances compared with the conventional linear-quadratic regulator(LQR) feedback controller.