As the technology of software developing fast, GIS component developed into a new stage ,ComGIS appeared . ComGIS is based on standard components in the platform. Between the various components may not only engage in a free and flexible restructuring, but also have a visual interface and easy to use standard interface. Design a component for net analysis of GIS. By separating internal functions in detail and designing interfaces logically,special and cooperative component are constructed.The gotten information of geography will be saved into database,then reading the information of geography from database to initial the road net data. User can search the map to get the way they want. The method A-Star algorithm (a utilizes Dijkstra algorithm) to solve the problems caused by the large amount of GIS data in searching, the speed of searching is improved totally, the shortest path between two points will be gotten in the shortest time, and show the path back to the user on the map.