Abstract: In the limit equilibrium method for slope stability analysis, it is difficult to consider the stress state of the soil and the calculation of slope sliding surface stress has relied on the finite element numerical method for a long time. To solve this problem, the idea of slope surface unloading and equivalent stress is proposed. After considering the slope surface as a semi-infinite boundary, the slope stress is solved by the elastic theory. Then the stability safety factor is calculated according to the slip surface stress. Finally, the position of the potential sliding surface, the stress distribution of the sliding surface and the safety factor are compared with the existing theories based on the several example. The research results show that the concept of slope surface unloading and equivalent stress is clear and conforms to the slope force characteristics. The sliding surface stress obtained by this method is basically consistent with the finite element calculation results. The searched potential sliding surface position and the corresponding stability safety factor are very close to the finite element strength reduction method and the limit equilibrium method calculation results. In addition, the calculation method can be effectively combined with prestressed support structures, reflecting the reinforcing effect of prestressing.