On analysis of the drawbacks of the current content delivery system, such as heterogeneous, isolated content service systems and difficult integration, a novel Web Services-based content alliance broker scheme - WS-CABroker, is introduced in this paper. Firstly, we propose the architecture of WS-CABroker for integrating heterogeneous content service systems based on Web Services standard. Then we describe the main function components included in the alliance platform. Furthermore, the paper studies and discusses the implementation mechanism of content integration and registration service module and media server status monitoring module, including flow chart and exchanged XML format. From our research experiences and related survey, we analyze the prospective research direction and challenges in this field, including WS-Resource Framework.