Soil nails have been commonly used for slope stabilization by enhancing the shear re-sistance of soil and the pullout resistance at the interface. In this study, a numerical model was proposed for stability analysis of a slope reinforced with pressure-grouted soil nails using the shear strength reduc-tion method. To confirm the effect of grouting pressure on the slope stability, a series of numerical anal-yses were conducted. Special attention is given to the installation effect of the pressure-grouted soil nail. Results show that the pressure-grouted soil nail increases the safety factor by fifty percent in a slope by increasing the overall stiffness of the nailed slope system. It is also found that the pullout resistance of a soil nail is the main factor for stabilizing slopes rather than the shear resistance of the soil nail.