It is recognized that the spatial organization of urban systems can be abstracted as three main components: point, line and area. Even though this substance of urban systems coincides with the main purpose of GIS for spatial or geometric data types such as point, arc and polygon, little attention has been given to this aspect. The potential analytical capabilities of GIS for international urban systems are demonstrated using a case study of the international urban system of China and Japan. It was found that obtaining unified digital base maps is a basic and important requirement for database building. Introducing the concept of graph or the conjunction of graph and map can present us infinite possibilities to develop new methods.