The bedrock of a crushed concrete gravity dam is a layered rock body. The seismic intensity is eight degrees, and part of the dam section is a folding-type foundation plane. In order to ensure the safety of the project and provide guidance for optimizing the elevation of the foundation plane, The coefficient of safety for slip stability of a typical section of the dam is obtained using the finite element stress integration method and the equal coefficient of safety method for the original design elevation and the proposed elevation under normal storage conditions and earthquake design. The results show that: (1) When the foundation surface is at 1420 m, the slip-resistance stability safety coefficient of the 4# dam section along the foundation surface under static and dynamic working conditions is greater than the specification's permissible value. However, the lower limit of the slip-resistance stability safety coefficient for the design earthquake working condition at a foundation surface of 1425 m does not meet the requirements. Therefore, it is suggested that the elevation of the foundation surface of the 4# dam section be 1420 m. (2) The results of the finite element stress integration method and the equal safety factor method used to analyze the slip resistance stability of the folded foundation surface gravity dam are close to each other and can be verified. (3) The lower limit value of the safety coefficient obtained by the equal safety factor method is conservative. These research results can serve as a reference for similar projects.