An　appropriate　nonlinear　mechanism　may　create　the　rogue　waves.　Perhaps　the　simplest　mechanism,　which　is　able　to　create　considerate　changes　in　the　wave　amplitude,　is　the　nonlinear　interaction　of　shallow-water　solitons.　The　most　well-known　examples　of　such　structure　are　Korteweg-de　Vries　(KdV)　solitons.　The　Korteweg-de　Vries　(KdV)　equation,　which　describes　the　shallow　water　waves,　is　a　basic　weakly　dispersive　and　weakly　nonlinear　model.　Basing　on　the　homogeneous　balanced　method,　we　achieve　the　general　rational　solution　of　a　classical　KdV　equation.　Numerical　simulations　of　the　solution　allow　us　to　explain　rare　and　unexpected　appearance　of　the　rogue　waves.　We　compare　the　rogue　waves　with　the　ones　generated　by　the　nonlinear　Schrodinger　(NLS)　equation　which　can　describe　deep　water　wave　trains.　The　numerical　results　illustrate　that　the　amplitude　of　the　KdV　equation　is　higher　than　the　one　of　the　NLS　equation,　which　may　causes　more　serious　damage　of　engineering　structures　in　the　ocean.　This　nonlinear　mechanism　will　provide　a　theoretical　guidance　in　the　ocean　and　physics.