Abstract: Based on the UMAT user material subroutine interface provided by the finite element software ABAQUS and by considering the impact of the Stress Lode Angle on the mechanical properties of clays, the critical state line in the modified Cam-clay model is improved. The elastic-plastic matrix is derived by introducing shear expansion ratio and using the correlated flow rule, thus developing the UMAT subroutine of the Cam-clay model considering the influence of the Stress Lode Angle. By using this subroutine, the static triaxial and true triaxial tests of the soils consolidated normally are simulated, and meanwhile the changes of the final settlement of the seawall, which is caused by changing the Stress Lode Angle, are analyzed. The results show that the Cam-clay model considering the Stress Lode Angle can well simulate the stress-strain characteristics of soil. The influence of the change in Stress Lode Angle on the final settlement of the seawall decreases with the increase of the foundation depth, with the influence on the final settlement at the seawall-foundation junction is the most significant.