Background　and　objective:　Coil　embolization　has　become　a　new　treatment　method　for　pulsatile　tinnitus　(PT)　caused　by　sigmoid　sinus　diverticulum　(SSD).　Although　this　therapy　has　achieved　good　results　in　clinical　reports,　the　hemodynamic　mechanism　of　coils　in　the　treatment　of　PT　in　SSD　remained　unclear.　Methods:　Finite　element　method　(FEM)　and　computational　fluid　dynamics　(CFD)　were　combined　to　explore　the　hemodynamic　mechanism　of　coil　embolization　in　SSD　treatment.　Three　personalized　geometric　models　of　sigmoid　sinus　were　established　according　to　the　CTA　data　of　patients.　Coil　model　were　established　by　FEM,　and　the　hemodynamic　differences　of　SSD　before　and　after　coiling　were　compared　by　transient　CFD　method.　Results:　Velocity　streamlines　disappeared　in　the　SSD　after　coiling.　At　the　peak　time　(t1　=　0.22　s),　the　SSD-average　velocity　decreased　in　every　patient.　The　average　value　of　the　decreased　in　three　patients　was　0.154　+/-　0.028　m/s　(mean　+/-　SD).　Wall　average　pressure　(P-avg)　also　showed　a　decline　in　every　patient.　Average　of　decrements　of　three　patients　was　17.69　+/-　4.91　Pa　(mean　+/-　SD).　Average　WSS　(WSSavg)　was　also　reduced　in　every　patient.　The　average　value　of　WSS　drop　was　9.74　+/-　3.02　Pa　(mean　+/-　SD).　After　coiling,　the　proportion　of　low-velocity　region　in　the　sigmoid　sinus　cortical　plate　dehiscence　(SSCPD)　area　increased.　Average　of　increments　was　22.1　+/-　5.36%　(mean　+/-　SD).　Conclusions:　A　reduction　in　SSD-average　velocity,　wall　pressure,　and　WSS　were　the　short-term　hemodynamic　mechanism　of　coil　embolization　for　PT.　Coil　embolization　increased　the　proportion　of　low-velocity　region　in　the　SSCPD　area,　thereby　creating　a　hemodynamic　environment　that　easily　produced　thrombus　and　protects　blood　vessels　from　the　impact　of　blood　flow.　This　phenomenon　was　the　long-term　effect　of　coil　embolization.　(C)　2022　Elsevier　B.V.　All　rights　reserved.