The　high-salt　fog　environment　under　a　marine　climate　affects　the　capillary　water　absorption　performance　of　porous　building　materials,　causing　changes　in　the　thermal　and　wet　properties　of　the　materials　and　in　their　structural　durability.　Therefore,　a　capillary　water　absorption　experiment　of　coral　sand　concrete　(CSC)　in　different　salt　solution　concentrations　was　designed　in　this　study.　The　experimental　results　showed　that　salt　had　the　effect　of　first　promoting　and　then　inhibiting　capillary　water　absorption　coefficient　(Acap)　with　increased　salt　solution　concentration.　Salt　had　the　effect　of　promoting　liquid　diffusivity　(Dl).　In　addition,　by　analyzing　the　surface　tension　and　viscosity　of　a　sodium　chloride　solution,　the　mechanism　of　the　influence　of　liquid　properties　on　Acap　was　briefly　explored.　The　results　provide　a　theoretical　basis　for　the　establishment　of　a　coupled　heat　and　moisture　transfer　model　of　porous　building　materials　in　marine　climates.