This paper presents the design, implementation and evaluation of an object-oriented simulator in an AMC operating on pull production control concept. The integration of decouplers into the AMC is also described. With the application of decouplers, the model of object-oriented simulator for control creates a revers flow between parts and information allows the minimum inventory level for production of AMC. Of particular interest is the design of internal object data structure and message passing algorithm to the object that closely resembles the actual activity of AMC with pull production control. The object-oriented simulator has been designed such that it can be run in simulation mode but can easily accommodate real-time event driven control of physical cells. The job sequence of the AMC system is modeled by object-oriented simulator with a time constraint to generate real time signals. The results of this paper can be applied to a AMC consisting many robots and conveyors.