Mangroves　have　a　remarkable　wave　dissipating　effect.　An　experimental　study　on　the　tsunami　impact　building　model　and　mangrove　protection　effect　was　carried　out.　The　dam　breaking　wave　was　used　to　simulate　the　tsunami　wave,　and　the　mangrove　and　building　models　were　installed　in　the　flume.　The　protective　effect　of　mangroves　was　studied　by　measuring　the　bore　height　before　and　after　the　tsunami　wave　passed　through　the　mangroves　and　pressure　during　tsunami　bores　impacting　buildings　and　pressure　around　the　building　during　tsunami　bores.　The　results　show　that,　in　all　cases,　bore　heights　reduced　by　mangrove　are　increased　by　building　obstruction.　On　the　premise　that　the　mangroves　are　not　destroyed,　the　disaster　mitigating　effect　will　not　be　affected　by　the　wave　intensity,　but　will　increase　with　the　mangrove　density.　Among　the　three　arrangements,　the　annular　arrangement　has　the　best　mitigating　effect.　The　process　of　the　tsunami　bore　impacting　the　building　is　divided　into　four　stages:　front-hitting,　run-up,　quasi-steady　and　recession.　Under　the　protection　of　mangroves,　the　pressure　at　each　stage　is　significantly　reduced.　For　front-hitting　pressure,　the　maximum　pressure　no　longer　appears　here　but　in　the　run-up　stage.　For　quasi-steady　pressure,　the　time　history　of　pressure　will　oscillate　due　to　bubbles　generated　when　the　tsunami　passes　mangroves.　According　to　Bernoulli　principle,　mangroves　are　determined　to　play　a　major　role　in　reducing　tsunami　energy.　Finally,　based　on　the　experimental　data,　equations　for　estimating　the　quasi-steady　pressure　in　the　center　of　the　lower　part　of　the　building,　and　the　distribution　of　pressure　on　the　building　are　presented.