The　connection　between　offshore　wind　power　foundation　structures　and　steel　pipe　piles　is　usually　carried　out　by　grouting.　With　the　development　of　offshore　wind　power　to　deep　sea,　the　grouting　connection　between　wind　power　foundation　and　steel　pipe　piles　is　deeper　and　deeper　in　underwater　position.　To　determine　the　influence　of　seawater　pressure　on　the　basic　mechanical　properties　of　grouting　material,　the　grouting　material　specimens　were　placed　in　a　pressure　vessel　for　curing,　and　then　their　basic　mechanical　properties　such　as　compressive　strength,　flexural　strength,　and　elastic　modulus　were　tested.　In　addition,　the　phase　composition　and　microstructure　were　analyzed　by　X-ray　diffractometer　and　scanning　electron　microscope.　The　results　show　that　the　compressive　strength　of　grouting　material　is　improved　after　curing　under　a　pressure　environment.　Seawater　pressure　does　not　produce　a　“wedging”　effect,　but　further　improves　the　compactness　of　grouting　material.　When　the　seawater　pressure　increases　from　0　MPa　to　0.　75　MPa,　the　compressive　strength,　flexural　strength,　and　elastic　modulus　of　grouting　material　increase　by　10.　7%,　2.　9%,　and　16.　7%,　respectively.　Seawater　pressure　does　not　change　the　phase　composition　of　grouting　material,　but　reduces　its　internal　porosity　and　increases　its　compactness,　thus　improving　its　mechanical　properties.　©　2024　Bulletin　of　the　Chinese　Ceramic　Society　Press.　All　rights　reserved.