To ensure the kilter to abstract and transfer information for Internet-driven collaborative design, a multi-granularity description and data structure of 3D geometrical model are presented. The multi-granularity description approach is composed of geometric knowledge of 3 D model, the form feature information relative manufacturing process and life-cycle of product. Traditionally, the roughness - granularity description was fastened excessively on the format of information presentation. On the other hand, the minuteness-granularity description emphasizes excessively the content of information presentation. This meant, that neither the pure roughness-granularity nor the pure minuteness-granularity presentation for 3D geometrical model, can meet all the requirements at certain phases during the life-cycle of the product. The multi-granularity description of 3D geometrical model, which integrated both of roughness-granularity and minuteness-granularity presentation, can reasonably, completely and fleetly, describe 3D geometrical model according to the design requirements of the collaborative designers.