Spatial data sharing is necessary for socialized Geographical Information Systems. It requires integrating spatial data in different formats. Data exchange through interchange file formats is a popular way to share data between different GIS or cartography software. Data exchange is a time and labor concerning way. We have to run one software package to export data to a specified interchange file, such as DXF, then, run another software tool to import it. The process is too complicated, and it will take us a lot of time when we need to frequently exchange mass data. Spatial Data Interoperation is an ideal way provided by Open GIS Consortium (OGC) to share spatial data among software packages. In this way, GIS software data accessing interfaces should comply with the standards formulated by OGC. We can then share spatial data among different software without exporting or importing. It requires each software package has OGC’s standard data accessing interfaces. Now, this is still not a practical way for spatial data sharing. The Seamless Integration of Multi source Spatial data (SIMS) technology is a spatial data accessing architecture. SIMS consists of three tiers, including data providers, data agent and data consumers. In this model, data consumers, such as analysis components, access data through data agent instead of directly accessing data providers. It has one data agent but can have more than one data provider. Each data provider is implemented for a specified software file format. SIMS not only provide capabilities to access (read and write) spatial data in different formats, but also gives user abilities to perform analyses among several kinds of spatial data formats. In this paper, the authors describe the SIMS technologic architecture, and discuss its development and application.