Abstarct: The U7 station as a support station is in middle of North-South section of Tehran Metro Line 7. This station is excavated before EPB arrival and for EPB services. To preventing of instability in launch and reception portals, should use the required arrangements. It is therefore necessary, first appropriate system is selected for stability of two portals; second geometric details and resistive stabilization systems for portals must be designed so that the technical, safety and economic factors be suitable. So the engineering design of specification stabilizer system plays an important role in reducing the cost of U7 launch and reception portals stability. Due to advances in computer and software, the numerical modeling of crossing the EPB machine at portals plays an important role in determining of qualitative and quantitative characteristics of the stabilizer system. In this thesis, first according to the existing problems in U7 station, suitable method for portals stability selected. Then by using the numerical modeling, the effect of tunnel boring and EPB drilling investigated machine in portals stability. Finally, by using the numerical modeling results, the most appropriate program le stability for port designed and selected.