With the rapid emergence of Web services, more and more Web services are published on the Internet as resources for Web application development. There may exist some relationships among different Web services, such as exact match, plug-in match, and irrelevant. In this paper, we discuss a set of requirements related to multimedia Web services, and propose a three-tier framework to establish an open environment supporting multimedia Web services, while partially implementing the requirements. This paper focuses on the design of the service broker tier that is essential for future Web servicesoriented system design and integration and enabling Web services more transparent, interoperable, and fault-tolerate. Keywords Multimedia Web services . Service broker . Three-tier open environment . Requirements