Abstract: Aiming at the current limitations of the method for slope stability under open-underground mining, first of all, according to the characteristics of slope stability under open-underground mining and the limit analysis method for slope stability based on the upper bound theorem of plastic mechanics, a mobile displacement field of submerged rock under longwall mining is established, and in the meantime, the equation for submerged rock is obtained accordingly by using the method of plastic limit analysis. Secondly, the submerged rock of southern Antaibao open-pit slope under open-underground mining is studied by using the method, and the influence of subsidence caused by underground mining on vicinal rock and slope stability are analyzed. The following measures are proposed: the boundary parameter should be established depending on the vertical height of safe mining between mining face and slope bench. Accordingly, the mining face should be bounded by 71460 (Y value) to ensure its vertical height of safe mining to be more than 105 meter, which can guarantee the stability of southern Antaibao open-pit slope under open-underground mining.