Abstract: In order to reveal the high-level instability mode of reverse dip slope under the influence of weak layer, taking the north slope of Fushun West Open-pit Mine as the engineering background, the occurrence position and occurrence of weak layer are determined by using the results of deep displacement monitoring. The shear strength parameters of weak layer are determined by parameter back analysis method. Using numerical simulation method, the high instability failure mode of reverse inclined slope under the influence of weak layer is revealed, and the control measures for the high-level instability of the slope are determined. The results show that the high-level instability mode of the reverse inclined slope under the influence of the weak layer is “sitting sliding along the weak layer”. When the slope cutting load is reduced to +2 m level and the groundwater elevation is reduced to -33 m level, the slope stability coefficient is increased to 1.316, meeting the requirements of safety reserve. According to the analysis of surface monitoring data in the landslide body, creep deformation still occurs during construction and tends to be stable after construction, and the slope control effect in the landslide area is remarkable.