Tunnel damage is aggravated by the interaction between cracks and earthquake loading. Thus, the study of the dynamic fracture of tunnel lining with cracks under earthquake loading is of great importance. In this study, the correctness of the simulated results was calculated by the two-dimensional finite element method, while the dynamic stress intensity factors for a plate with a stationary crack under dynamic loads were first computed by the interaction integral method. The numerical results were then compared to the analytical solutions, with whom they were found to be in good agreement. The computational results showed that the interaction integral method can be used to obtain accurate dynamic stress intensity factors for cracked structures under dynamic loads. Subsequently, the method was used to calculate the dynamic stress intensity factors and the bearing capacity safety factors for the lining of heavy haul railway tunnels with cracks. The Xixian heavy haul railway tunnel located in the south-central area of the Shanxi Province was considered as a case study, with additional consideration given to twelve working conditions. A 2D finite element model was established in order to compute the dynamic fracture of a tunnel with cracks under earthquake loading. The results showed that under the seismic loads, the dynamic stress intensity factors of mode I cracks controlled the safety of the tunnel structure. Thereby, if the length of the crack was greater than a certain value, the tunnel was assessed as dangerous.