In analyzing the inundation area attributed to the sea level brought about by climate change, previous researchers derived a different inundation area from the actual one by applying a uniform sea level rise without taking into account the regional mean sea level. This study has attempted to analyze the inundation area by devising a sea-level rise scenario that considers the regional mean sea level of the study area. In addition, a comparative analysis was conducted on the area of inundation vulnerabilities between the sea level rise scenario that takes into account the regional mean sea level and one that does not. As a result of study, an error between the actual mean sea level and topographic elevation was corrected by using the height of the tide observation data of the area. Next, a total of nine scenarios on the sea level rise of the Taean region (SLR-T 1.1~SLR-T 3.3) were devised using the IPCC SRES scenario, RCP 8.5 scenario, height of the tide data and storm surge height, among others. Finally, the results showed that the inundation area by scenario was at least 4.17km2(SLR-T 1.1) up to 168.41km2(SLR-T 3.3), which was about 45% less than that of the scenario devised without considering the mean sea level that reflects the regional differences. In other words, results of the analysis on the inundation area using conventional methods turned out to be wider than that of the actual inundation area.