Abstract: The problem and challenge of the GIS applied in the hydrology are analyzed and discussed. On the basis of the data structure of the Arc hydro,the data organization and implementation of the spatial hydro-data model are discussed and studied with respect to the object-oriented technology. The hydrologic object's spatial locations,feature attribute,temporal attribute and their topological relationships could be well represented in the object-oriented GIS hydro-data model. Finally,the object-oriented GIS hydro-data model is applied to the Qingfengshan Basin. The application result shows that the object-oriented GIS hydro-data model provides a common structure frame for the hydrological spatial data and is helpful to promote the wide application of GIS to the hydrology.