Taking Xiandian arch dam in Peng'an County of Sichuan Province as an example, the initial 3D finite element model based on the finite element method was established to be applied in Xian Dian arch dam and its foundation. Taking the dam and its bedrock as ideal elastic plastic materials, the sandwich type crack model based on the Drucker-Prager yield criterion and the method of displacement mutation was used to simulate crack of dam shoulder and analyze the stress stability of the dam. The results showed that it was reasonable and feasible to consolidate grouting with low pressure thick paste and backfill with C15 fine stone concrete buried stone on the basis of completely removing the landslide collapse. This method can not only provide experiences and references for other similar engineering projects, but also can be widely applied to the construction of water conservancy projects in the future.