The rapid advance of networking and componentization technology is one of the most important characteristics in software development in recent year. The main breakthrough in software technology is in software cooperation and componentization. Based on the achievement of relative study home and abroad,this paper introduces the combination of COM technology and WebGIS. Arming at the particularity of GIS, this paper describes the necessity, feasibility, common process and main task of using COM to construct WebGIS. At last, this paper describes how to import COM technique to the field of WebGIS in order to improve the level of WebGIS technique and work efficiency, utilize the efficiency of WebGIS fully.