By contrasting the traditional way in which GIS was completed that comes with less flexible, low efficiency, and lack redundancy which cause high entry cost, the fast development of microkernel plug-in technology provides the lightweight, efficient and scalable solution to Geographical Information System (GIS). This paper is to reveal the potential of microkernel plug-in geospatial information processing technology in GIS design and practice, with the acceptance and usage of function model called Resource loading manager(RLM) for GIS applications, which provides a possible solution to overcome the GIS's high cost issue. After the short review of microkernel plug-in technology, the possibility of GIS design with microkernel is analyzed. This paper also introduced the composition of the whole system and the design of GIS service platform based on middle-ware in detail.