The complex interaction and the high costs of modern manufacturing systems make it necessary to evaluate their use performance. Production scheduling problem is one of the key problems of research of manufacturing systems since with a proper scheduling, the utilization of resources is optimized and orders are produced on time which improves the shop performance and associated cost benefits. However the complexity of modern production systems makes the use of analytical tools more difficult. Thus a computer simulation model of the existing computer integrated manufacturing system based on the control logic that describes the operation of the system is developed to test the performance of different scheduling rules with respect to mean flow time, machine efficiency and total run time as performance measures. According to the results of experiments, the model agrees with the real system.