In　order　to　study　the　law　of　evolution　of　erosion　time　on　the　impermeability　of　soil-cement　in　the　marine　environment,　permeability　tests,　X-ray　diffraction　(XRD)　tests,　and　scanning　electron　microscopy　(SEM)　tests　were　conducted　on　ferronickel　slag　powder　(FSP)　soil-cement.　The　changes　in　the　permeability　properties　of　the　soil-cement　under　different　soaking　age　conditions　were　investigated.　The　results　show　that　the　marine　environment　has　little　influence　on　the　impermeability　of　soil-cement　at　an　early　age,　and　that　their　permeability　coefficient　is　essentially　identical　to　that　of　clear　water.　The　impermeability　of　soil-cement　in　the　marine　environment　decreases　significantly　after　28　days,　and　it　continues　to　decrease　with　age.　However,　the　deterioration　in　impermeability　of　soil-cement　caused　by　the　marine　environment　can　be　alleviated　after　FSP　is　added　to　the　soil-cement,　and　a　better　mixing　value　of　40%　is　obtained.　At　the　same　time,　the　regression　curve　equation　of　the　permeability　coefficient　of　soil-cement　with　the　change　of　age　is　established.　FSP　exerts　a　microaggregate　effect　and　chemical　activity　in　the　soil-cement.　It　not　only　improves　the　compactness　of　the　soil-cement　matrix　but　also　prevents　the　penetration　of　corrosive　ions　into　the　soil-cement,　thereby　improving　the　impermeability　of　the　soil-cement.