This study aims to generate a risk evaluation methodology for the aged dam structure by coupling the micro and macro models created by hydraulic computation and discontinuous deformation analysis (DDA) with numerical manifold method (NMM), respectively. For the macro analysis, DDA+NMM is an energy-convergence algorithm and can be utilized to estimate critical loading based on the potential joints existing within the discontinuous block system. Due to the micro view, the relationship of groundwater level and precipitation can be studied by using hydraulic computation based on the groundwater flow equations. The proposed method presents an evaluation procedure for modeling an aged earth dam with efficient and economic open-source programs. As the result, the simulation can help determining the criterion of risk factors and the prevention strategy.