The　seismic　response　of　underwater　tunnels　in　the　saturated　soil　is　studied　by　ABAQUS,　with　the　site　soil　simulated　by　the　pore　pressure　element　deduced　from　fluid-solid　coupling　dynamic　model　of　fluid-saturated　porous　media.　Calculated　results　illustrate　that　to　the　single-hole　tunnel　in　the　saturated　soil,　the　pore　pressure　of　the　soil　near　the　bottom　of　tunnel　is　maximal　by　the　end　of　the　input　earthquake　wave.　At　that　moment　the　value　of　the　pore　pressure　of　the　soil　located　in　two　sides　of　tunnel　is　equal.　On　the　other　hand,　to　the　double-hole　tunnel　in　the　saturated　soil,　the　value　of　the　pore　pressure　of　the　soil　between　two　tunnels　is　positive,　while　the　value　of　the　pore　pressure　of　the　soil　below　the　tunnels　is　negative.　The　value　of　the　stress　of　two　tunnels　is　equal.　In　the　meanwhile,　it　is　shown　that　the　pore　pressure　element　deduced　from　fluid-solid　coupling　dynamic　model　of　fluid-saturated　porous　media　is　effective　to　the　study　of　the　seismic　response　of　the　underground　structures　in　the　saturated　soil.　©,　2015,　The　Editorial　Board　of　Journal　of　Basic　Science　and　Engineering.　All　right　reserved.