Foundation pits with dualistic structure of soil stratum and underlying rock stratum were commonly across Qingdao area. Aiming at the characteristics of “endsuspended pile”, numerical simulation with Finite Element Method(FEM) and analysis was carried out to study the design methods and other influencing factors, such as stability, depth of the pile body, axial stress of anchor and width of reserved rock shoulder. It was shown that traditional design methods were applicable for the upper soil stratum, with the excavation stability guaranteed. The increase in embedded depth of pile body or axial stress of anchor led to effective control over excavation stability and deformation of the underlying rock stratum. And the axial stress was the main controlling factor, hence intense monitoring should be carried out on the stress during the course of construction. The larger the width of the rock shoulder was, the smaller the displacement of piles would be. When the width exceeded a certain value, its influences on the displacement and bending moment of piles tended to be insignificant.