Abstract: This paper discusses the problem of guaranteed cost fault-tolerant control for networked control systems with data packet dropout.Based on a more general model of actuator continuous gain faults,considering a class of networked control systems with Markovian packet dropout,the packet dropout dependent Lyapunov function is constructed with Lyapunov stability theory and Markovian jump linear system theory.The sufficient conditions for the existence of the controller is given,which guarantees the mean-square stability of NCS and meets the guaranteed cost performance,and the corresponding guaranteed cost fault-tolerant controller design techniques are also provided.Simultaneously,the optimal guaranteed cost fault-tolerant controller is constructed by solving the optimization problem.Finally,the numerical example and simulations are provided to prove the validity of the proposed method.