This paper proposes a design procedure to develop the object-oriented simulator of port container terminal. The design methodology uses an object-oriented approach to support an object-oriented simulation and the design procedure consists of object scheme and event scheme. The object-scheme is a procedure to determine the structure of material flow objects and information flow objects and a relation diagram between objects that have attributes and methods. The event scheme is a procedure to define methods and to connect messages of objects. We assume that the container terminal system consists of gate, container yard, and berth and the equipment used in the container terminal are container cranes, transfer cranes, yard tractors, and trailers.