Taking a slope containing strongly weathered mudstone as the research object.According to the design method of orthogonal test and numerical simulation，the influence of different factors on the mechanical characteristics of pile slab wall was analyzed.The design parameters of pile-slab wall were optimized based on the research conclusions.The embedding ratio is the main factor affecting the maximum shear stress at the front corner of the pile and the maximum shear stress in the middle of the retaining plate.The distance width ratio is the main factor affecting the horizontal displacement at the top of the cantilever section of the pile body and the amount of concrete in the pile slab wall.After optimization，the maximum shear stress at the front corner of pile and in the middle of the retaining plate is reduced by 13.14% and 16.97% respectively，and the amount of concrete used in the pile slab wall per kilometer of slope support is reduced by 9.09%.