Active　faults　pose　significant　threats　to　the　structural　integrity　of　mountain　tunnels　in　seismic　active　zones.　Post-earthquake　reconnaissance　revealed　that　numerous　tunnels　were　damaged　during　past　earthquakes,　specifically　those　crossing　active　fault　zones.　In　this　study,　the　structural　response　and　damage　mechanism　of　a　water　conveyance　tunnel　subjected　to　reverse　faulting　was　investigated.　A　three-dimensional　finite　element　model　incorporating　the　cohesive　interface　elements　was　developed　to　simulate　the　nonlinear　process　of　the　reverse　fault　rupture.　The　ground　deformation　and　tunnel　damage　characteristics　predicted　by　the　numerical　analysis　were　in　good　agreement　with　the　field　observations　and　experimental　results,　which　proved　the　feasibility　of　the　proposed　simulation　scheme.　Moreover,　a　parametric　study　was　conducted　to　estimate　the　effects　of　dip　angle,　surrounding　rock　property,　tunnel　rigidity,　and　friction　coefficient　between　linings　on　tunnel　performance.　The　results　showed　that　the　damage　zone　with　softer　rock　masses　of　grade　IV　to　V,　based　on　the　Chinese　Guidelines　for　Design　of　Highway　Tunnel,　generally　led　to　moderate　structural　damage　to　the　tunnel.　The　tunnel＇s　performance　in　the　damage　zone　can　be　further　enhanced　by　increasing　tunnel　rigidity　and　smoothness　of　the　external　surface　of　the　secondary　lining.