With the frequent occurrence of marine oil spills, there is a growing demand for analyzing and publishing oil spill disaster information. It's a trend to research on the Open GIS based spatial information analysis and publishing. This article develops the Marine oil spilling monitoring information analysis & publishing system based on DotSpatial, the upgrade version of the open-source .NET development of component library. In this system, the oil spilling monitoring information is visualized, rendered, analyzed, and finally published to the web. However, open GIS is functionally limited and instable. It can not read the spatial information of RS images well, and the mapping and outputting module is unstable. This article solves some technical problems. For example, the spatial data are processed such as re-projected via GDAL (Geospatial Data Abstraction Library) to match the images layers with the vector layers. Vector oil spots data are generated and rendered, and the major axis and minor axis are drawn. Moreover the map extent to output can be determined by dragging a rectangle by GDI+, and the decorating of the map to putout is also improved. By adopting several developing method comprehensively, this article does research on the system development based on Open GIS platform to provide reference for other similar system researches and developments of spatial information expression and analysis.