Mangroves　are　crucial　for　protecting　coastal　areas　against　extreme　disasters　such　as　tsunamis　and　storm　surges.　An　experimental　study　was　conducted　to　determine　how　mangroves　can　mitigate　the　tsunami　wave　propagation.　The　test　was　performed　in　a　flume,　where　mangrove　models　were　installed　on　a　slope,　and　dam-burst　waves　were　used　to　simulate　tsunami　waves.　To　study　how　mangrove　forests　reduce　the　impact　of　tsunamis,　this　paper　measured　the　heights　of　the　incoming　waves　under　different　initial　conditions　(tsunami　wave　intensity　and　initial　water　depth)　and　plant　factors　(arrangement　and　distribution　density)　and　described　the　reduction　process.　The　results　show　that,　after　passing　through　the　mangrove,　the　tsunami　bore　height　will　decrease　within　a　certain　range　as　the　initial　water　depth　increases.　However,　there　is　no　correlation　between　the　increase　of　inundation　level　and　the　drop　of　water　level.　The　bore　height　attenuation　is　more　significant　at　higher　density　of　mangroves,　but　after　tsunami　passing　through　the　mangroves,　the　relative　bore　height　will　decrease.　When　the　distribution　density　of　mangroves　is　constant,　the　wave　attenuation　at　different　locations　(before,　on　and　after　the　slope)　shows　different　relationships　with　the　initial　water　depth　and　wave　height　for　different　models.　The　transmission　coefficient　(Ki)　shows　a　parabolic　correlation　with　its　density.　The　proportion　of　the　energy　loss　caused　by　the　mangrove　resistance　to　the　total　energy　(Eb)　is　defined　as　Cm2.　The　variation　trend　of　Cm2　corresponds　to　the　tsunami　wave　energy　attenuation　rate　(Ca)　and　Ki.　©　2023,　Chinese　Society　for　Oceanography　and　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.