SVG based on XML is a kind of language describing 2D vector graphics.It is usability and applicability to set up WebGIS.The paper puts forward a system structure of WebGIS based on SVG,which has been applied to campus electronic map system of Chongqing University.It has been proved the method is feasibility and practicability.The paper sets forth some key techniques of implement of the system in detail: coding method of organizing SVG spatial data;generation of SVG electronic map;storage of SVG spatial data and implement of client.