The fault fracture zone is one of the key influencing factors on the structural stability of a tunnel in high earthquake-intensity area. Aimed at dynamic interaction characteristics between surrounding rock and fault under seismic action，a dynamic contact force method considering various contact states was established. The method considers point-to-point contact and point-to-surface contact in finite element model， and it can simulate four contact states between the rock and fault: bonded contact， static contact，separation and sliding contact. Therefore，it is suitable to study the nonlinear large slip problem of dynamic contact system composed of the rock and fault under seismic load. First，the rationality of the method was verified by a sliding block example. Then， the method was applied to the anti-seismic stability calculation of Xianglushan tunnel in Dianzhong water diversion project. The influences of three working conditions on seismic response of the tunnel were contrastively analyzed: without fault， with fault but without dynamic contact，and with fault and dynamic contact. The results indicate that the existence of fault fracture zone aggravates the seismic reaction of the tunnel，which mainly appears as displacement and stress increase of the lining as well as failure zone enlargement of the rock. When considering the dynamic contact，the evident alternate displacement forms between the rock and fault during seismic loading procedure，and then exerts destructive effects on the lining. The damage zone of the lining mainly distributes in the place where the fault passes through and within about 10 m range of distance from both sides of the fault， and the lining in hanging wall is greatly affected by the fault. Under the motivation of horizontal seismic motion，the stress and displacement of the lining haunch are significantly larger than that of the top and bottom arch，so that the haunch is considered as the weak part of the lining structure.