In this paper, the slope of the side wall of a reservoir floodway is taken as an example, and the anchor retaining wall is used as the research object. Based on the theory of calculating the soil pressure distribution of the anchor retaining wall in the Chinese code, the numerical model is established with finite element software, adopts the inverse method to simulate the wall construction and anchor construction, and also considers the relative friction between the anchor anchored section and the soil body after grouting, solves the change of anchor rod axial force and the soil pressure distribution process of the elevated anchor retaining wall model under different working loads, and proposes an improved analytical formula based on the theoretical solution for solving the soil pressure distribution of the specification and the soil pressure and displacement distribution of the wall. The method also proposes an improved analytical formula for solving the normative earth pressure distribution based on the theoretical solution, which provides a theoretical basis for future engineering design optimization.