Being　one　of　the　potentially　important　hydrous　phases　of　the　lower　mantle,　it　is　important　to　study　the　properties　of　phase　H　to　understand　the　structure　and　composition　of　the　mantle.　The　crystal　structure,　elastic　modulus,　and　seismic　wave　velocity　of　phase　H　under　different　Fe　concentrations　(0,　12.5,　25,　100　at%)　at　16-60　GPa　were　calculated　by　the　first-principles　simulation.　The　density　of　phase　H　linearly　increases　with　increasing　Fe　concentration.　The　iron　concentrations　of　35.5-84.3　at%　lead　to　densities　matching　the　mantle　density　profile　at　different　depths　of　the　Earth.　The　effects　of　Fe　on　different　elastic　constants　show　varying　tendencies.　The　K　value　increases　with　the　Fe　concentration,　while　the　G　value　decreases.　The　values　for　Vp　and　Vs　increase　almost　linearly　with　the　rise　in　pressure.　The　Vp　and　Vs　values　decrease　with　increasing　Fe　content.　The　wave　velocities　of　the　pure-Mg　phase　H　and　Fe-bearing　phase　H　are　close　to　the　typical　velocity　of　the　Earth　at　500-1400　km　depth.　The　FeOOH-AlOOH-MgSiH2O4-FeSiH2O4　system　may　be　responsible　for　the　observed　seismic　properties　of　LLSVP　in　the　Earth＇s　lower　mantle.　The　quantitative　effect　of　Fe　on　the　density,　elastic　moduli　(K　and　G),　and　wave　velocities　(Vp　and　Vs)　are　listed　as　fitted　equations.　These　results　help　to　infer　the　Fe　concentration　and　structure　of　the　deep　Earth.