To make multimedia data easily retrieved, we use metadata to describe the information, so that search engines or other information filter tools can effectively and efficiently locate and retrieve the multimedia content. Since many features of multimedia content are perceptual and user-dependent, user modeling is also necessary for multimedia information retrieval systems, e.g., music information retrieval systems. Furthermore, to make the user models sharable, we need standardized language to describe them. In this paper, an XMLlike language is proposed to describe the user model for music information retrieval purposes. We also propose some paradigms to acquire, deploy and share the user information to improve current music information systems. A prototype system, MusicCat, is analyzed and implemented as a case. KEYWORDS User modeling, music information retrieval, XML, MPEG7