Aiming at the fault problem of certain type gun coordinator during the swing process, the virtual prototype technology was used to study the problem. By using ADAMS and AMESim software, the virtual prototyping model and hydraulic system model of the coordinator were established. The correctness of the prototype was verified by co-simulation combined with the experimental data. The fault was simulated by setting friction, motor voltage and leakage in the hydraulic cylinder. The simulation results were compared with the normal simulation values, and the influence of different fault parameters on the simulation results was obtained. The results show that the method can be more real, accurate and effective to study the dynamic characteristics of the coordinator. It can be used as a reference for fault diagnosis and repair.