Abstract: To address the problem of robust fault detection for networked control systems with Round-Robin protocol in which the sensor saturation and external disturbance are concerned, we propose an approach for designing a fault detection filter under the constraint of communication protocol. The sufficient condition for the existence of the fault detection filter is derived by applying Lyapunov stability theory and linear matrix inequality technique, and the corresponding optimal filter parameters can be obtained by solving a convex optimization problem. The designed filter not only ensures the asymptotically mean square stability of the filtering error system but possesses a much better disturbance-restraint ability. The effectiveness of the proposed method is verified by a numerical simulation and a DTS200 three-tank leakage detection test.