The reinforcement by geotextiles or geogrids helps to improve the embankment stability and guarantee more uniform settlement. The factors effect on the stability of the reinforced embankment on soft clay, in terms of slope stability and sliding resistance has been studied using a finite element program (GEO5 program). In this paper, the effect of geogrid Spacing, the height of the first geogrid layer, unit weight of embankment fill, and the angle of internal friction was studied. The numerical model results indicated that the optimum spacing between the geogrid layers is 0.5 m.  Increasing the angle of internal friction for the embankment fill causes to increase the factors of safety. Increasing the density of the embankment fill causes to decrease the factors of safety. Also, it was recommended to install the first geogrid layer between the embankment base and underlying soft clay layer without any vertical distance.