Abstract <p>In this paper, we study a robust fault-tolerant controller design method in networked control system (NCS), with denial of service (DoS) attack on both sides of the controller and in the presence of faults and packet dropouts at the control system nodes. In this paper, we present the existence condition of a robust fault-tolerant controller with state feedback in NCS with passive component faults and design a robust fault-tolerant control algorithm from Lyapunov’s stability theory. The main contributions of this paper are as follows. First, we develop a model of extended linear discrete NCS with packet dropout in the uncertain NCS model where passive component faults and DoS attacks exist, and present the existence condition of robust fault-tolerant controller. Second, from the model of the extended linear discrete uncertainty NCS, a robust fault-tolerant controller, a security controller, have been designed. The proposed security controller does not need to estimate the threshold value for the faults of passive components and is independent of fault detection and diagnosis devices. Finally, the effectiveness of designed robust optimal fault-tolerant controller is demonstrated through numerical simulations and application experiments for quadrotor unmanned aerial vehicle (UAV). In a networked control system, it can be used to protect network resources and verify the stability of the system.</p>