Abstract: To study the change law of the open-pit combined underground mining and superimposed disturbance on the stability of the side slope of the open-pit mine under different coal seams production, according to the occurrence conditions and mining methods of coal seams, the coal seam production under the side slope are divided into three types, including the horizontal state, rightward inclination and reverse inclination. The numerical simulation method is used to study the distribution of high stress area, the deformation degree and the damage extent. The variation law of slope stability under the same mining process and dip angle of different coal seams is obtained. The results show that the larger the dip angle of coal seam is, the larger the influence range of high stress area on both sides of the working face is. It is necessary to reasonably control the distance between the position of open cut and the slope surface, which can avoid the influence of the high-stress area of the mining on the slope stability; the greater the dip angle of the coal seam under the end is, the greater the damage extent of the slope after the mining is. When the coal seam is in the state of the rightward inclination, the damage degree to the slope is greater than the horizontal occurrence state, and the degree of damage caused by the reverse tilting state is less than the horizontal occurrence state; the rightward inclination of side slope for the coal seam is not conducive to the slope stability, and the reverse inclination state of the coal seam is conducive to the slope stability.