As a typical geological structure, soft interlayer is a key factor affecting the safety and stability of the entire slope. In order to better analyze the properties of soft interlayers and their influence on slope stability, for a mine open-pit rock slope with soft interlayer, the orthogonal control method was used to simulate the four occurrence states of the sandwich depth, inclination angle, quantity and structural surface spacing between the layers of the slope soft interlayer, and the stability and deformation law of the slope were revealed under different occurrence states.The results show that: (1) The occurrence state of the soft and weak interlayer of the slope has a significant impact on the stability of the slope, and the safety factor of the slope increases with the increase of the burial depth of the soft interlayer, and the safety factor of the slope tends to be stable after the burial depth reaches a certain level. (2) With the increase of the angle of the soft interlayer, the failure mechanism is manifested as interlayer mismotion, creep slip along the layer and progressive change of shear-slip along the soft structural surface; (3) With the increase of the number of soft interlayer layers, the overall decline of the slope leads to uneven deformation, the safety factor of the slope decreases, and the horizontal displacement increases; (4) Compared with the soft sandwich slope with the same buried depth structural surface spacing is small, the structural surface spacing has less influence on the slope safety factor.