Abstract: In order to solve the increasing problems of information isolated island and enterprise integration in integrated information service systems of modern enterprise, the authors introduce how to build information service system with Service-Oriented Architecture (SOA) and how to integrate J2EE platform and Domino system with Web service technology. J2EE platform and Domino system are two primary information service systems solutions. In our architecture, the two system are selected to implement different sub-system components according their own advantages. Web Service is exploited to integrate those components to a uniform service platform. Based on such a platform, various applications are designed with Web Service composition. In this way, sub-systems are well connected and diversified information and resources can be easily and effectively shared. This method provides a good reference for building enterprise information service system and integrating various systems and information.