Abstract: This paper analyzes three aspects of the reasons,the spatial data source,the spatial data representation and organization and the spatial data processing.On the basis of these analyses,we advanced some new concepts about the seamless spatial database,such as logical seamlessness,physical seamlessness,logical querying,physical merge.We also proposed the ways to implement the seamless spatial database in different levels.The problems of storage,access and dynamic segment in the physical seamless spatial database are also discussed in detail.