The repressive layer plays an important role in improving the stability of the seawall on the soft soil foundation,but the width and thickness are mostly calculated and selected by empirical formula and limit equilibrium method.Based on the strength reduction method,this paper studies the relationship between the width and thickness of the repressive layer and the safety factor of the seawall by using ABAQUS finite element software.First,the basic principle of strength reduction method is introduced.Then the relevant sea wall model is established.The width and thickness of the repression layer are added to the model in the form of the width and size of the linear load,and the safety factor and the potential sliding surface are calculated by taking the convergence of numerical calculation as the evaluation standard.The reasons of the change of safety factor and width of repressive layer are analyzed from the angle of sliding surface.The results show that the stability of the seawall is proportional to the width and thickness of the repressive layer,and the safety factor and the sliding surface do not change after the width exceeds a certain number.