This study describes the life cycle cost of unreinforced and reinforced soil slopes subjected to seismic forces according to their seismic deformation. The life cycle cost is the sum of the initial construction cost obtained from the actual construction information and the reconstruction cost assumed based on certain reconstruction methods. From the results of the seismic life cycle calculation, the life cycle cost obtained for the reinforced soil slope is observed to be lower than that of the unreinforced soil slope. The study demonstrates the efficiency of the life cycle cost evaluation rationally and quantitatively.