The earthquakes are one of the most important factors in the threat of underground structures. As Iran country is located in a seismic zone, considering the dynamic response of underground structures in this region is very important. Investigstion show, in the earthquake event, applied stresses to the tunnel structures, caused by Structure-Ground interaction, which product moment and force. So investigated tunnel behavior aganst the axial, torsional and shear forces, also bending and torsion moment. Especially study bending moment and axial forc. Because of importance of the spillway structures, they need high seismic level study. In this study, applying oftware which is a 3D finite difference commercial software. The stability of spillway twin tunnels of Roudbar Lorestan dam was investigated against earthquake seismic loads. The tunnels are located in Dalan formation and considering the stability of them needs special attention as tunnels alignment include a crushed zone whose thickness is 40 meters. Based on seismic studies, the dam site has a high potential of seismicity and include a lot of large and small active faults. The seismic study was done based on three levels of seismicity, which are MDE, SEE and MCE. The accelerograms designed based on response spectrum site in Roudbar Lorestan pumped-storage hydroelectricity, Bam and Bojnourd earthquake accelerograms and then scaling them according to the target’s response spectrum. The spillway tunnels of Roudbar Lorestan dam, were self stable under static loads. Due to seismicity of this area, vicinity of active fault such as Saravan-Baznavid fault and the significance of stability of these tunnels the cast-in place concrite with thickness of 70 cm was used as a final support. Assuming different concrete strength and steel percentage, four typs of concret lining were analysied in each seismicity level. The most appropriate lining based on the economical and safty consideration has a minimum strength of 30 MPa and steel percentage of 2.3%. It was also found that the use of steel in concrete lining, greatly increases the bearing capacity of structure in bending. According to Bending Moment_Axial Force diagram, the value of bending moments and axial forces were in the allowable range for proposed lining. The safety factor level is estimated to be at least 1.5 at the MCE level where the highest horizontal shear stress is achieved. At MCE level the maximum bending moment and axial force in the final lining is 1.2 MN.m and 6.8 MN respectively. The maximum bending moment taking in place along the crushed zone and other zones have a low value of bending moment. It is clear that the safety factor for other levels will be much higher than the MCE level. At the MCE level, the residual bending moment was about 80 times higher than the static condition,and it is several time tolerated in the process of applying the load. This ratio for axial force is at least 35 times, which remains in as a residual force, which has not caused any disturbance in system stability.