The southern tidal flat of Kanghwa Island with an area of approximately 90 km² is one of the biggest flats on the western coast of Korea. Remote sensing has been identified as potential tool to provide synoptic information of the intertidal environments. To estimate quantitatively the morphological changes in a tidal flat, it is necessary to measure both the amount of sedimentation or erosion and the sediment facies involved. Thus, the objectives of this study are : (i) to generate an intertidal digital elevation model (DEM) using the waterline method around 1989; (ii) to quantitatively estimate the morphological changes from the generated DEM for the years 1989 and the extracted waterlines for the year 2002; (iii) to discriminate the surface sedimentary facies by texture analysis and classification method, using high-resolution satellite data such as IKONOS and Kompsat EOC; iv) to ultimately evaluate the morphological changes with respect to sedimentary facies. The morphological changes are dependent upon the sedimentary facies. The changes in sand or mixed flats are greater by at least three times than that in the mudflats. Although we are not able to assess the accuracy of the estimation of morphologic changes, the resulting trend of sedimentation or erosion is complied with the general rule of sedimentology. The results demonstrate that satellite remote sensing is a more efficient tool for estimating long-term morphologic changes in the tidal flats