Abstract: Based on the shear-lag model, the interaction mechanism between reinforcement and soil matrix in the reinforced earth retaining wall is analyzed. A hypothesis is proposed that the axial stress in the reinforcement comes from the shear displacement of the surrounding soil matrix and that the surrounding soil matrix will bear the shear stress only. The soil matrix in reinforced soil unit is separated into outer layer and inner layer. The stress equilibrium differential equation for the reinforcement is established, and a formula which describes the distribution rules of the axial stress in reinforcement is brought forward. According to the theoretical analysis, the proposed formula can show non-linear distribution, and a maximum value point xof the axial stress in the reinforcement is x≤ L/2 (Lmeans the reinforcement length). The axial stress in the reinforcement of reinforced earth retaining wall will have only one maximum value when the reinforcement is horizontal, and multi-maximum values will arise when the reinforcement is concave or convex along the reinforcement length. The reasons of the occurrence of multi-maximum values of reinforcement axial stress in reinforced earth retaining wall and the phenomenon of the potential rupture surface close to the wall panel near bottom wall can be explained according to the research results.