The KTX has been launched one month ago and people can travel much faster and further. There are two opinions which are the dispersion and the concentration of metropolitan population. These contrary opinions were disputed against each other before launching KTX. The phenomena of metropolitan population concentration socially made many problems as it was already pointed out on many papers. So accurate prediction is very important. Thus, this study will predict how KTX will affect the dispersion of metropolitan population focused on highly populated Seoul-Pusan Railway. It will achieved by comparing and analysing foreign cases.