Abstract: The classical Mohr-Coulomb model for soil is a linear elastic-perfectly plastic model in which yield strength and failure strength are identical. In practice, however, once soil yields, its strength and deformation behavior differ from those in the elastic stage, and strain softening may occur. The classical Mohr-Coulomb model therefore cannot represent this behavior, which may lead to theoretical deviations between calculated and actual results. To address this issue, a Mohr-Coulomb strain-softening model was developed based on the modified Mohr-Coulomb criterion proposed by Abbo and Sloan. Equivalent plastic strain was introduced as the softening parameter, and the shear-strength softening process was represented by establishing a relationship in which soil cohesion decreases with increasing equivalent plastic strain. An implicit backward Euler integration algorithm was used for stress updating, and the softening process was solved in two stages: brittle drop and plastic correction. A user material subroutine (UMAT) for the proposed model was developed in Abaqus. Numerical simulation of conventional triaxial compression tests shows that the model reliably reproduces the post-peak softening stage of the soil stress-strain response and accurately reflects the peak and residual shear strengths. Comparisons between the proposed model and the conventional Mohr-Coulomb model in a soil-slope analysis show that the proposed model gives a lower factor of safety because it considers the actual condition that soil strength in the plastic zone is lower than that in the elastic zone. Theoretically, the more fully the plastic zone develops near the potential sliding surface inside the slope, the larger the difference between the two calculated safety factors. The proposed model can therefore evaluate actual soil slopes, especially slopes with developed internal shear-plastic zones, more accurately and has considerable application value.