This paper developed an operating software for the manufacturing cell of a model plant. The model plant, which was manufactured by Fishertechnik, consists of an assembly cell, a machining cell, and supplementary material handling equipments. Each I/O module of the model plant communicates with the INTERBUS controller devices via High-level Language Interface(HLI). The machining center has two machining cells, which consists of 4 machines respectively, two 3-axis portal transporters, and a rail guided vehicle(RGV). The Petri-Net was used to investigate the dynamics of each machining cell, e.g., the relation of material handling equipments and machines. The operating software was analyzed and designed by Object Oriented Technique. The software was implemented using Delphi 3.0 under Windows 95/NT operating system.