The problem of fault detection for the aeroengine's nonlinear distributed control system is studied.First, an nonlinear model in the form of polynomial combination is established for the aeroengine by using the identification method.Then, in consideration of the network factors, a model with random time delay is established for the aeroengines nonlinear distributed control system.After that, the nonlinear distributed control system is regarded as a random system, for which a nonlinear fault observer is designed.The fault observer error systems mean-square asymptotically-stable working condition in the form of Linear Matrix Inequality (LMI) is derived by applying the Lyapunov stable theory and the mean-square asymptotically-stable theory of the random system, and a feasible LMI solution is also obtained.Finally, the specific steps of fault detection are given, and the validity of the proposed fault detection algorithm is verified through simulation.