A　series　of　undrained　cyclic　torsional　shear　tests　are　carried　out　on　the　saturated　coral　sand　specimens　from　Nansha　Islands　by　using　the　hollow　cylinder　torsion　shear　apparatus.　The　aim　of　the　tests　is　to　investigate　the　effects　of　fine　contents(FC),　relative　density　(Dr)　and　applied　cyclic　stress　ratio　CSR　on　the　generated　excess　pore　pressure　ratio　Ru　of　the　specimens.　The　test　results　show　that:　the　development　rate　of　Ru-N　curve　increases　with　the　increasing　FC　and　CSR,　but　decreases　with　the　increasing　Dr.　In　addition,　the　development　rate　of　Ru-N　curve　of　the　saturated　coral　sands　significantly　exceeds　that　of　the　terrestrial　quartz　sands,　and　the　traditional　Seed　pore　pressure　model　is　not　fully　applicable　to　characterize　the　development　pattern　of　the　excess　pore　pressure　of　coral　sands.　For　the　same　Dr　and　FC,　Ru　of　the　specimens　under　different　CSR　is　uniquely　related　to　the　shear　strain　amplitude　(γa).　A　pore　pressure　evaluation　model　based　on　the　shear　strain　characteristics　is　established,　and　the　analysis　shows　that　the　pore　pressure　model　parameter　A　is　a　soil-specific　constant,　and　the　density-corrected　pore　pressure　model　parameter　B/(Dr)1.5　has　a　single　negative　power　function　relationship　with　the　equivalent　skeleton　void　ratio　esk*.　©　2023　Chinese　Society　of　Civil　Engineering.　All　rights　reserved.