Web Services is the focus of IT fields at present. The purpose of Web services is to provide a common technology layer that has no relation with language and platform. The application of different platforms, special in E-business system needs this technology layer to connect and integrate dynamically with each other. Firstly, this paper introduces simple the concept and architecture of Web Services and analyzes the core technologies to construct Web services, XML, SOAP, WSDL and UDDI in detail. Secondly based on Web services and BPEL4WS technology, an open and distributed dynamic E-business system structure is brought out and realized. Finally, the front design done on dynamic E-business system is summarized and further work is prospected.