Due to the Climate Change and Climate Variability in the world, the temperature, precipitation, evaporation etc, hydrologic cycle components are changing rapidly compared with the past. Previous researches have presented many results of extreme hydrological events and frequency increases. In Korea, during latest 10years (1999~2008), the frequency of localized heavy rain above 100 mm in a day occurred totally 385 times, compared 1970~80s when the frequency was 222 times, it increased 1.7 times. For 2011, from early July to mid-August, due to the rainy season and localized heavy precipitation, the accumulated precipitation reached 1285.3 mm. In Seoul and metropolitan areas, the localized heavy precipitation over design precipitation of 100year frequency happened, causing widely flooded area and causing property damage and human casualties in the downtown area. According to the latest extreme flood moved to upper tail of existing probability density function, it is expected that future flood damage frequency and intensity will increase comparing present situation. In this paper, in order to project the future influence of extreme flood of the Korean peninsula, comparing the IPCC 5 Report (AR5), according to the Representative Concentration Pathways (RCP), newly promoted and simulated regional climate model was applied to summary precipitation and considering to the exterior factors, the non-stationary frequency analysis was performed. This result range across the South Korea areas, and the whole increase of extreme precipitation was checked. Especially, following to RCP 4.5 and 8.5 parts, the future 20year frequency average would be reduced to 12.5years, 11.9years separately in the place, so it is expected that the flood safety will be reduced.