Abstract: Spatial object representation is a basic problem of GIS,and it is based on spatial object classification. A good classification model is not only good for decribing(constructing) spatial objects, but also good for revealing spoilal relations, and helpful for normalizing and systematizing spatial analysis methods. In this paper, after analyzing some spatial concept models and spatial object classification models, we proposed basic principles for classification along with a new spatial object classification model,in this model, we define seven basic spatial objects, namely, simple point, complex point, simple line, directed simple line, complex line,directed complex line and polygon,we also explained how to construct complex spatial objects with these basic objects.