A　time-domain　method　for　the　analysis　of　arch　dam-foundation　rock　dynamic　interaction　during　earthquake　was　proposed,　and　the　dynamic　relaxation　technique　was　adopted　to　obtain　the　initial　static　response　for　dynamic　analysis　by　[Du　et　al.　(2005).　The　paper　has　been　contributed　to　Bulletin　of　earthquake　engineering].　In　this　paper,　a　nonlinear　explicit　method　in　time　domain　considering　the　opening　and　closing　effect　of　contact　joints　on　arch　dam　during　earthquake　is　further　proposed　by　introducing　the　dynamic　contact　force　model　into　the　method.　The　simulation　accuracy　of　dynamic　contact　force　model　is　verified　by　comparing　its　calculation　result　and　test　result　of　scale　model　on　shaking　table.　Finally,　the　influence　of　joints　on　the　seismic　response　of　Xiaowan　arch　dam　is　studied　by　the　proposed　method　and　some　conclusions　are　given.