Every year one of slope instability that damages the lives of many people would enter the landslide. Therefore, understanding the factors affecting the landslide is one of the most essential measures to prevent landslide damage is reduced. Stability analysis of soil slopes in order to determine the most probable failure surface, ie the lowest confidence level, Geotechnical Engineering is one of the important issues. One key factor which may stability of soil slopes, especially roadside slopes to endanger, there is a landslide or the landslide. soil Geostudio (SLOPE / W) has any impact on the safety factor (F.S) to Shirvani, will be studied. AUTO CAD to design the transverse profiles and the list of calculated volumes and density test have been conducted at the site. Also, using cross sections, the most critical point mode selected and the scope (to drift) software SLOPE / W. And in this regard, with trial and error soil shear strength parameters software has been determined.The results showed that the effect of the natural slope, road construction on slopes with a gradient steeper than 24 degrees reduces slope stability and reliability result in the stability range of solutions slope protection such as the implementation staircase gable (width of stairs 3 meters and the step height of 4 meters 1.25: 1). in this regard, the slope safety factor increased about 28 percent. The results showed trenching operation to a height of 4 meters with a slope of 1:1 stable and 9 meters on the slope of the trench 1:1 becomes unstable. It can be concluded that the operations slope excavation and road margins has a direct effect on the stability of slopes.