Simulation is most widely used technique when it is infeasible to execute the actual process of system because of overriding factors such as time or money. Recently, expert systems have been applied as vehicles for developing intelligent simulation environments. In this thesis, we developed a simulation system integrated with expert systems, and applied to a well-known NP complete problem-production scheduling problem. Expert systems are used for supporting complex decisions occurring during simulation. The developed system has a user-friendly interface, checks consistency between data and has feedback process as an active process that tries to achieve goals through feedback rules. This approach may improve intelligence in simulation experiment.