Abstarct: Massive traffic jams and limited ground areas had led to more usage of underground tunneling in the urban areas. The Twin tunnels Hakim has been excavated in the length of Approximately 1 km with NATM method in 7 phases and 2 side galleries. The width of the tunnel is 17.8 and its height is 13.8. The support system which is design by the engineers regarding to its geology conditions is a combination of shotcrete and lattice girder. Although lattice girder has wide usage in the support system but a few researches have been done in this matter. The purpose of this thesis is designing a shotcrete support system with lattice girder by finite difference method and FLAC2D software and analyzing geometric and strength properties of lattice girder. The suitable support system for hakkim tunnel is suggested with equivalent section method by convergence rate and the ground reaction curve with FLAC2D and ground relaxation in the model. Then the stability of tunnel is analyzed for different excavation phases of tunneling by interaction diagrams (axial force–bending moment and axial force–shear force interaction diagrams). Then the results of FLAC2D is compared with monitoring tools that have been installed in the tunnel which had good accordance. It was compared to SAP 2000 software and the support system performance was analyzed for different loads combination and we can conclude that tunnel support system, respond perfectly to loading. Finally, the sensitivity analysis of the tunnel is done to evaluate the effect of the geometrical parameter (lattice girder shape, diagonal of the bars (cross section), the width and height of lattice girder) and the strength parameter of the lattice girder. The results indicate that geometrically the diagonal of the bars and the height of the lattice girder and aspect strength the yield strength, have the most influence on the stability of the support system. on the other hand between two lattice girder with the same cross section and height, the 4-bars lattice girder has more structual stability.