QBIC (query by image content) is a method to query image by characteristics of the object (or region) of the image, which include color, shape texture and spatial relations. This new research project combines technique of IP (image process), IR (image recognition) and IDB, is a very prospecting domain. The authors deal with the investigation and realization of querying images by the shape of image objects(or region) in this paper, which includes: (1) the cognitive process of shape; (2) a set of characteristic to describe shape of image object; (3) an efficient match algorithm for image querying; (4) a prototype system for querying image by the shape of image objects, which named Photo Engine.