Abstract: Outwash deposits is located in the dagu station dam selection, the scale is huge, once the failure will directly affect the safety of dam construction. According to the field geological survey, analysis of Material composition and structure characteristics, the establishment of geological model, calculated its stability by limit equilibrium method, calculation results show that, outwash body as a whole is in a stable～basically stable state, the leading edge of the existence of local instability, to the dam site less affected, that can provide scientific basis to slope excavation and supporting.