This paper discusses the basic theory and notation how component technology is applied to the WebGIS, and gives an overall introduction to the prevailing developing method of component WebGIS. Based on a given WebGIS' component platform and an Object Related Database System (Oracle Spatial), the paper develops a successful WebGIS application,and analyses the shortcomings and merits of component technology applying to the WebGIS.It is put forward that component technology is a new developing method and more effective,flexible and powerful compared with the present or traditional developing technology. Moreover, it provides more flexible choice for integrated development. With ASP(Active Server Page),components are integrated to web page, program developed is tested applicable in the intranet.