Saemangeum tideland reclamation project in Korea has been started in November 1991 to construct 33km long sea dikes, 28,300 ha of land and 11,800 ha of freshwater lake. By the end of 2004, 85% of the planed construction works for sea dikes, sluice gates were completed. In May 2001, Korean government has proclaimed an environment-friendly development policy as a result of NGO- Government joint investigation and open discussion for two years since 1999. And multidisciplinary survey program on the oceanic environment in the Saemangeum area has been started in early 2002. Physical, chemical, biological and geological oceanographic survey and in situ monitoring were included in the program.We established a integrated data management system of the multidisciplinary survey program. The integrated data management system was designed to present its service through internet web site. Its data service system was based on a metadata management system. The metadata management system provides information of observation according to user defined query condition such as locations and time, etc. And end-users could get the final observation data were linked with the metadata. The results of observations were also provided as a product of visualization on Geographic Information System (GIS) for each observation items. And real-time observation data were another major part to compose the data management system. In situ observation data from buoys in that area for oceanographic and atmospheric parameters were transmitted to data server and processed results were displayed graphically as well as numerically on the data service web site.