Coral　reefs　thrive　in　complex　marine　geological　environments　and　are　likely　to　suffer　from　dynamic　marine　disasters.　The　liquefaction　characteristics　of　saturated　marine　coral　sand　subjected　to　dynamic　loading,　such　as　ocean　waves,　submarine　earthquakes,　storm　tides,　volcanic　activities,　and　hurricanes,　are　key　factors　affecting　the　safety　of　coral　reefs.　A　systematic　study　is　conducted　through　a　series　of　hollow-cylinder　torsional　shear　experiments　on　the　undrained　response　of　saturated　marine　coral　sand　with　different　non-plastic　fines　contents　(FCs)　under　cyclic　linear　stress　paths　with　various　cyclic　loading　direction　angles　(αd).　An　interesting　discovery　is　that　the　cyclic　linear　stress　paths　with　angles　αd　and　90°−αd　have　the　same　stress　effect　on　liquefaction　characteristics　under　isotropic　consolidation　condition.　The　test　results　show　that　if　the　near-zero　effective　stress　state　is　defined　as　the　criterion　for　initial　liquefaction,　then　the　liquefaction　resistance　of　saturated　coral　sand　decreases　with　increasing　αd　or　FC.　The　generation　of　excess　pore　water　pressure　(EPWP)　presents　three　modes:　(1)　“rapid–stable–fast,”　(2)　“rapid–stable,”　and　(3)　“fast　linear-like.”　Moreover,　an　energy-based　EPWP　prediction　method　is　established.　A　novel　discovery　is　that　the　generalized　shear　strain　amplitude　(γga)　is　uniquely　related　to　the　EPWP　ratio　of　coral　sand　for　a　given　relative　density　and　FC.　In　addition,　by　introducing　unit　cyclic　stress　ratio　(USR)　as　a　new　index　of　liquefaction　resistance,　a　common　correlation　between　equivalent　skeleton　void　ratio　esk*　and　USR15　(required　for　initial　liquefaction　in　15　cycles)　is　established　for　all　test　cases　considered.　This　is　confirmed　by　the　experimental　data　of　five　types　of　terrestrial　siliceous　sands　reported　in　the　literature.　©　2023