The invention discloses an MPEG-7-based image retrieving system, which mainly comprises three key techniques, namely, characteristic extraction, content description and searching engine. The MPEG-7-based image retrieving system comprises (1) content-based image retrieval CBIR, (2) a multimedia content description interface MPEG-7 and (3) a database model and management. Specifically, the MPEG-7-based image retrieving system comprises a characteristic extraction module, a retrieval module, an output module and a query module, and realizes network function-oriented image content-based query, so that a user can quickly and effectively retrieve image resources. A descriptor specified by an MPEG-7 standard is improved so as to obtain remarkable retrieval effect and perform combined query on different visual characteristics, such as colors, textures and shapes. The image retrieving system is developed for digital libraries, medical application and trademark retrieval application, and an algorithm is optimized according to the MPEG-7 standard, so that the MPEG-7-based image retrieving system reaches a leading domestic level in terms of algorithm study and application. The MPEG-7-based image retrieving system has the characteristics of clear technical direction, smooth development and relatively stronger maturity.