This paper aims to introduce System Dynamics (SD) in applying Drum Buffer Rope (DBR) methodology of Theory of Constraints (TOC) in a three-stage flow shop system that produces a single product. To the best of our knowledge, although there are a lot of TOC applications using discrete simulation in production scheduling with DBR methodology, there are not any TOC application of DBR methodology in production scheduling using System Dynamics. We firstly present a conceptual model of the production planning and control and raw material procurement processes of a flow shop, based on the concept of the Capacity Constraint Resource (CCR), which is the corner stone of the TOC philosophy. Then, we present the stock and flow diagram of the system under study. According to the results of an illustrative example, it reveals that the driving force of the production and raw materials procurement processes of the flow shop is its CCR schedule. The system response to pulse and wavy changes in demand is examined as well. Moreover, by means of the simulation results, the efficiency of DBR production scheduling approach is contrasted with the well known anchoring and adjustment approach of Sterman.