Recently, assessment of vulnerability of existing dam structures is a rising key issue in aspects of entire life year from design, construction to maintenance even in Korea due to more frequent earthquakes and effects of climate change. This study aims to develop a vulnerability assessment method for existing dam structures by using fragility analysis method based on 2-D FEM analyses, which can take into consideration various uncertainty information to dam structure safety assessment, and which may be incorporated into an integrated safety management platform under development by K-water.