Abstract. Based on the scientific and technical research project "Data Collection and Decision Support System for Hydropower Dam Construction", which is set up by the Chinese National Development and Reform Commission, this paper, which aims to solve the problems in managing the construction of large-scale hydropower project, focuses on the knowledge portal using Web Services and J2EE.After studying China Gezhouba (Group) Corporation (CGGC), which is building the largest hydropower project of the world, Three Gorges Project, a multi-layer architecture and a supporting system for the knowledge portal is put forward. The method for integrating existing resources is also proposed. Enterprise application integration (EAI), which is platform-free and improving the interoperability of heterogeneous system, is realized by interoperability in distributed environment, software combination technology, heterogeneous system integration, and application mid-ware specification. All the resources are in the open and unified environment and are easy to share. The process of designing and developing knowledge portal for CGGC Operation Management System is further provided to illustrate the architecture proposed above.