Through field tests on a four-level reinforced soil high steep slope project, the distribution law of vertical stress at the base of a multi-level spun high-strength polyester geotextile reinforced high steep slope was studied. The results showed that the vertical stress at the base exhibited a nonlinear distribution along the direction of the reinforcement material, with the maximum value occurring at the end of the reinforcement material. Using PLAXIS 2D, numerical simulations were conducted on the cross-section of a four-level reinforced soil steep slope to study the changes in structural characteristics such as horizontal soil pressure on the back of the backfill body, horizontal deformation of the slope surface at each level, geotextile strain, and potential fracture surface of the slope. The influence of factors such as reinforcement length, spacing between reinforcement materials, friction angle inside the filling material, and platform width on the horizontal deformation characteristics of the slope was also analyzed. Research has shown that the horizontal soil pressure on various levels of slopes undergoes a sudden change at the platform, exhibiting a serrated distribution along the slope height; The horizontal deformation of slope surfaces at all levels shows obvious "bulging" phenomena at different positions; The strain of geotextile at different heights shows a nonlinear distribution along the direction of reinforcement laying, and pre-sents two distribution forms: "double peak" and "single peak"; There are two types of potential fracture surfaces for slopes: integral circular sliding fracture surfaces and composite fracture surfaces. It was further found that the spacing and length of reinforcement materials significantly impact the horizontal deformation of high and steep slopes.