Concept of watershed data model is from geodatabase. Watershed data model is the description of meaning ，behavior and role of features in a watershed，which demanded by integrated watershed modeling and management. Taking the Xitiaoxi watershed，which is located in the upper reaches in Taihu Basin，as a case study, the drainage was divided into three types： watershed, flood control area and polder. Different stream-lake networks were constructed in these three drainage types: tree type stream-lake network, which include lake ( reservoir)， Dou, stream，hydrological points, in nature drainage ( watershed)； nel type stream-lake network，which include flood control area, polder, lake, wetland，canal, stream and hydrological points，in artificial drainage. If the scale of drainage is selected suitably, any complex water network in the middle and lower reaches of the Yangzte River can be described by these two type stream-lake network. Features included in any of drainage type and relationships of each other were constructed in this paper, which can be helpful for watershed data model construction in China.