This　paper　takes　an　offshore　continuous　rigid　bridge　as　the　background　bridge　to　reveal　the　dynamic　response　law　of　an　offshore　bridge　under　the　action　of　earthquake　and　tsunami.　A　tsunami　wave　is　simulated　by　a　dam-break　wave.　A　numerical　model　of　a　dam-break　impact　of　a　bridge　pier　is　established　in　Fluent　software,　and　k−ε　turbulence　model　is　chosen　to　solve　the　Navier–Stokes　equation.　Meanwhile,　ABAQUS　software　is　used　to　establish　a　three-dimensional　nonlinear　full　bridge　model.　The　dam-break　wave　working　condition　is　proposed　according　to　the　Stoker　theory.　The　bridge　dynamic　response　index　under　a　single　earthquake　action　and　a　continuous　earthquake　tsunami　action　is　calculated,　and　the　dynamic　response　rules　under　the　two　actions　are　summarized.　The　results　show　that　compared　with　the　tsunami　action　alone,　the　sequential　action　of　the　earthquake　and　tsunami　will　cause　a　greater　dynamic　response　of　the　bridge　structure.　With　the　increase　in　the　height　of　the　incoming　tsunami　wave,　the　waveform　trend　difference　of　the　response　index　will　be　more　significant.　Moreover,　the　influence　coefficient　of　the　dynamic　response　index　of　the　bridge　tends　to　increase　as　the　probability　level　of　the　earthquake　occurrence　decreases.　©　2023　Elsevier　Ltd