Ocean observations and numerical modeling have performed cyclic long-term routine to measure thevarious kinds of marine and coastal environment information and analyze the specific phenomenon.From that, numerous data have accumulated and it is hard to handle and utilize without systematicdata management and scientific visualization. Therefore, for the rapid interpretation anddissemination of useful information through the web, it is necessary to develop the real-time Web-GIS based integrated coastal information service system of automatic data collection,implementation of marine geo-database and proper data representations and visualization. It willcontribute to coastal environment monitoring, forecasting and policy decision. In this work, we haveimplemented Web-GIS-based coastal environment-information service system about on theSaemangeum coastal area. It can be utilized the coastal environment management and conservationfrom the development such as improvement of water quality, offer of warning and protection.