The invention discloses a fault detection method for a positive linear network control system based on a robust filter. Firstly, according to the current situation of networked control system with time delay and uncertainty, a discrete model of positive linear networked control system is established, and the corresponding robust filter is designed accordingly; based on this discrete model and filter, an augmented system is established, Then, by scaling the upper and lower bounds of the uncertain parameters, the augmented system is derived as a positive system, which is stable and satisfies l 1 / l ‑ (robustness / fault sensitivity) is a sufficient condition for performance; finally, through an iterative algorithm, combined with the optimization objective, the filter parameters are solved, that is, while taking into account the robustness and fault sensitivity, the fault of the positive linear network control system can be realized. detection. Through the iterative algorithm, the invention greatly widens the application range, improves the efficiency of fault detection, and can be applied to various sensory / non-sensor fault systems with uncertain parameters.