In order to address the relative lack of research on the stability of deep foundation pit excavation in layered rock mass with slopes containing high inclination and external inclined structural planes, based on the foundation pit project of the South Third Ring Station of Xuzhou Metro Line 3, a transversely isotropic elastic-plastic ubiquitous joint model was obtained by improving the existing ubiquitous joint model in FLAC^3D, which could comprehensively consider both deformation and strength anisotropy of layered rock mass. With the adoption of the constitutive model, deformations of foundation pit and retaining structure under different rock dip angles were simulated and analyzed, the results manifest that both the maximum value of ground settlement and the maximum horizontal displacement of retaining piles are affected by the dip angle of rock stratum, with the two values achieving the maximum under the dip angle of 50°. Additionally, with the aim to quantitatively analyze the deformation law of retaining piles under the influence of various rock dip angles, data fitting was performed on the simulation results, the theoretical relationship between the maximum deformation of retaining pile and the dip angle of rock stratum was obtained. The strength reduction calculation results show that the safety factor is the lowest when the dip angle of rock is 50°, the distribution of safety factors and potential failure surface forms of the slope after excavation of the foundation pit under different rock strata inclination angles are obtained, and the optimization suggestions for the spacing of retaining piles are given.