Based　on　the　cnoidal　wave　theory,　an　analytical　solution　for　the　diffraction　of　cnoidal　incident　wave　around　a　large　elliptical　cylinder　in　shallow　water　is　derived　in　elliptical　coordinates.　Accordingly,　the　analytical　expressions　for　the　pressure　and　wave　forces　are　obtained.　In　order　to　validate　the　analytical　model,　a　numerical　model　for　the　diffraction　of　cnoidal　incident　wave　around　a　large　cylinder　with　an　arbitrary　cross-section　is　also　developed　using　finite　element　method,　where　the　whole　fluid　domain　is　divided　into　bounded　and　unbounded　domain.　The　exact　artificial　boundary　condition　is　introduced　to　model　the　unbounded　domain.　The　proposed　numerical　model　is　used　to　verify　the　present　analytical　solution　for　the　cnoidal　incident　wave　forces　on　the　elliptical　cylinder.　Based　on　the　present　analytical　solution,　the　detailed　analysis　on　the　cnoidal　wave　forces　on　elliptical　cylinders　are　performed.　It　is　found　that　the　maximum　dimensionless　wave　forces　obtained　by　cnoidal　wave　theory　are　obviously　larger　than　those　obtained　by　small　amplitude　wave　theory.　Therefore,　ocean　engineers　should　consider　the　cnoidal　wave　forces　in　the　design　offshore　structures　with　an　elliptical　cross-section　in　shallow　water.　©　2020　IEEE.