Abstract: To solve the problem of uncertain time delay in networked control systems (NCS), the uncertain of time delay was converted to the uncertainty of parameter matrixes, and the model of NCS was simplified as an uncertain discrete model with time delay. The guaranteed cost control problem for NCS was translated to a robust guaranteed cost control problem for an uncertainty discrete system with time delay based on the above model. Lyapunov theory and linear matrix inequality (LMI) were applied to prove the sufficient condition of guaranteed cost control for NCS was equivalent to solving a LMI by a static state feedback. Simulation results show effectiveness of the proposed control method.