In this paper, arch dam foundation interaction was analyzed by using 3 D spline boundary element method(3DSBEM). With spline interpolation approaching shape of arch dam, infinite spline boundary element modeling the fondation, transfer matrix method to solve substructure problem, particular solutions method adjustedby singularity for calculationg boundary stress. We abandon arch beam simplification and foundation F. vogt suppositions in traditional arch stress analyses.Even with coarse division, we can ob...