Abstract: According to a retaining wall failure instance on 205 National Road in Shandong Province of China, the numerical simulation method was used to analyze the effect of slope angle on the retaining wall stability under vehicle loading. The results show that slope angle can sensitively influence the whole stability of the retaining wall. The horizontal deformation and plasticity scale of the retaining wall increase with increasing slope angle, and the slippage of the slope can result in additional deformation of the retaining wall. During the construction of the retaining wall on a slope, the effect of slope angle should be considered to determine the whole reinforcement scheme for roadbed, wall, and slope body.