Spatial information technology based on the “geological information system(GIS)” is the natural and best way for building “Digital Valley” engineering. Aiming at study and development of simulation system of flood routing and regimen and hydrology in Qingjiang River, this paper analyses valley's geological data feature and advantages and disadvantages of traditional GIS in “digital valley” engineering. In order to satisfy three-dimensional demands of simulation system, this paper addresses object-oriented spatial data model and data structure of valley's geographical entities based on traditional GIS which manages and deals with various previous basic geographical spatial data and attributes of valley in two-dimensional format, which displays valley geographical sight according to three-dimensional format, and satisfactory effect can be achieved in real study. This three- dimensional data format can meet various demands of “digital Qingjiang” engineering at various stage, such as integrated transaction, analysis, evaluation, decision-making and three-dimensional visualization.