High flexibility and a quick response of the flexible manufacturing system make it extremely complicated to properly control the production activities. In this paper, the complicated FMS control problem is studied. The coloured Petri net is chosen to model the flexible manufacturing systems, presenting a generic functional view. Based on this model, an expert system is developed to improve the decision-making ability of the FMS control system. The expert system developed is flexible enough to be adapted to a variety of real-life applications. A simulation is performed on a practical flexible manufacturing system.