Taking Yangzhou Polytechnic College at Yangzijing as an example, this paper takes Google Earth as the data source, ArcGIS and Tianzheng software as the modeling platform. According to the existence of architectural working drawing, the paper establishes schemes of modeling digital city by two ways: ① controls position of buildings by ArcGIS, then models buildings in ArcGIS or does refining treatment in SketchUp; ② controls position of buildings by ArcGIS, then introduces architectural working drawing into ArcGIS directly. Finally all data will be fused in ArcGIS platform. These two methods make the modeling of digital city rapidly and effectively, and reduce the cost greatly. A preliminary investigation has also been carried out on the application in the field of urban planning, housing marketing and digital navigation.