Abstract: To investigate the strengthening effect of cantilever reinforcement, a plastic-damage model of concrete and the steel-stiffening approach for modeling steel-concrete interaction are used to analyze the seismic response of high arch dam with and without the presence of reinforcement. The calculated results show that this measure reduces the nonlinear response of an arch dam, e.g. joint opening and the relative deformation of dam crest, and limits the extension and opening width of cracks. It is concluded that cantilever reinforcement is beneficial to improving the earthquake-resistant capacity of the arch dam. The results also show that the strengthening effect of the proposed reinforcement is insufficient for the engineering demand. Therefore, cantilever reinforcement should be modified and optimized for the arch dam.