The main purpose of this research is to investigate the scouring effect on the west coast of Taiwan that has been caused by the natural disasters and the human activities since 17 centuries. The studies consist of the depicting of maritime topography, the data collection of sea meteorology, and the data mapping with the use of Google Earth software. The present research employed the satellite image data and the achieve maps from literature for accurately quantifying the coastal changes in south-western Taiwan. The changing process of coastal line around the south-western Taiwan including the influences of natural and artificial factors of long and short period is also investigated. The surveys has divided the coastal changes into three periods, 17th century to 1904 A.D., 1940 A.D. to 1945 A.D., and 1945 A.D. to present. In the first period, the isotope dating and historical data we used to identify the coastal line. The results of this research showed that the main element of coastal line shift in the west coast between 17th ~20th century is caused by the sink-transport of enriched river-based sources. During the second period, the data collection with the use of better precision instruments from colonial government, the sea area of Yunlin produced series of shoal from 1904 to 1945. The coast area expanded outward 26 km. On the contrary, the shoals in the sea area of Tainan were shifted inward due to lacking of sink-transport source, but the coasts remained less deposited in this period because the influence of artificial facilities construction. By artificial development, the coast was seriously corroded frequently since 1945 that leaded to the shoals reduction and disappearance. The coast was no longer to receive the sink transport source because of highly artificial coastal development, such as land reclamation, fishing port construction, and coastal protection measures to prevent from further continuously erosion around the coasts. It is necessary to emphasize that the theorem, practical and research aspect can be applied to integrate the coastal plan and development in the future. It is imperative for government to initiative on the aspects of monitoring the topography, river basin, ecology area, and sea meteorology with the use of GIS system to establish database. Moreover, the government should evaluate the feasibility of coast construction, revise the laws to protect coast and provide the guidelines on the coast plan and development in the marine environment. Finally, this research addresses the need of precautionary approach against the natural disaster.