To　study　the　effects　of　seepage　and　earthquakes　on　a　subsea　tunnel　structure,　a　subsea　tunnel　passing　through　a　fracture　zone　was　selected　to　be　studied.　The　surrounding　rock　was　defined　as　a　continuous　porous　medium.　Considering　the　visco-elastic　artificial　boundary　and　fluid-solid　action　between　the　surrounding　rock　and　pore　water,　the　finite　element　software　ADINA　was　used　to　analyze　the　variation　of　pore　water　pressure　in　the　tunnel　surrounding　rock　during　horizontal　seismic　action,　the　effects　of　hydrodynamic　pressure　in　a　porous　medium　on　the　tunnel　lining　and　the　effects　of　the　combined　action　of　a　porous　medium　seepage　field　and　seismic　stress　field　on　tunnel　safety　and　stability.　The　numerical　calculations　show　that　the　effects　of　hydrodynamic　pressure　in　a　porous　rock　medium　on　the　structural　internal　force　of　a　tunnel　during　seepage　is　significant　and　must　be　addressed.　Additionally,　the　stresses　and　strains　at　the　spandrel,　the　springing,　and　both　sides　of　the　tunnel　lining　increase　dramatically　under　seismic　action.