Based on previous research on spatial conceptual data model of GIS, the authors present an object-oriented holistic GIS data model, and discuss data organization, data storage and access mechanism of holistic GIS system. Firstly, six features of holistic data model are introduced, and a conceptual data model is presented with a key concept, Complex Object, which is introduced in detail. Secondly, data organization means of holistic GIS are introduced. Several basic concepts such as Object Set, Layer, Da...