The article analyzes two approaches of product visualization,and brings forward a common approach of product data to achieve Web visualization based on IGES standard. It transforms CAD data to universal and useful 3D data, it don't need special browser, and it is very simple and useful. A technological process is introduced to transform Web formats from IGES data. The article also describes concretely triangle anatomy of entity, and the minutia arithmetic of curve face. The principle that triangle piece realize to transform to VRML format is described. With the verification in the prototype system, this approach is proved with reason and credibility.