Web service based data exchange has been the trend of EAI. We can create Proxies to expose existing systems as web services. There have been some tools that can help users to construct web services on the basis of existing systems. However, authority control and dynamic service configuration are not taken into account in the process of construction. In this paper we present an EAI-Oriented unified authentication model, and then put forward the serviceitems-based authority control and dynamic service configuration management in the construction of EAI-oriented web service architecture. Tool support in the process of construction is also discussed.