Abstract: High-piled wharf is widely used in port construction in the southwest region of China. The pile foundation pile is liable to be deformed horizontally after pile back filling, especially in the case of deep backfill pile deformation, which is more serious, thus affecting the normal use of foundation piles and even security and stability. Based on the model test of the slope foundation pile, a pile-soil refinement numerical analysis model for the deep filling slope pile is established to study the effects of the filling thickness, internal friction angle, pile cross-section size and other design parameters on the internal force and deformation in the deep filling slope. Research shows: with the increase of the backfill depth, the displacement distribution of the pile gradually changes from straight to S, and the maximum displacement of the pile gradually moves down from the pile top to the backfill, and the pile body force is increaseing with the thicknes of backfill. When the shear strength of the backfill material is increased little by little, the pile body deformation can be effectively controlled. However, when the shear strength of the backfill is increased to a certain extent, the displacement of the pile remains basically unchanged. Increasing the shear strength of backfill material has a limited effect on controlling the deformation of pile. When the support pile diameter is small, the pile body has S-shaped deformation, thus increasing the pile diameter and decreasing the pile bending deformation, but excessive use of large-diameter pile may cause the pile to produce a large displacement. The paper puts forward a h-type double-pile optimal support scheme, which provides technical support for the design and construction of the pile foundation of the inland port.