Taking a high rocky slope in Guizhou Province as an example, the deep hole monitoring data of the three-stage platform pile reinforcement before and after the reinforcement is analyzed. After the reinforcement about the slope, the displacement of the deep monitoring hole was still increasing, and the slope was still unstable. Secondly, the slope condition of the three-stage platform after reinforcement is analyzed inversely by FLAC3D finite element difference software. A reinforcement model for changing the position of the anti-slide pile is established, and the displacement, shear strain increment and the position of the slip zone are analyzed. The corresponding slope stability coefficient is obtained and the optimal reinforcement scheme is put forward. Thirdly, the results show that the stability coefficient reaches the highest quantity of 1.25 in the pile body located at the secondary platform through the simulation calculation of the optimal reinforcement scheme. After reinforcement, the maximum displacement is reducing by 22.5%, and the shear strain increment located in the post-slip zone is reducing by 20.69%.It provides a theoretical analysis method for guiding the subsequent reinforcement and treating the landslide.