In　this　article,　we　conduct　a　numerical　simulation　to　investigate　the　failure　mechanism　of　natural　fibre-hydrogel　composites　under　tensile　deformation　and　swelling.　Firstly,　a　physical-based　constitutive　model　is　chosen　to　describe　the　deformation　of　the　hydrogel　matrix.　Concurrently,　a　macroscopic　phenomenological　hyperelastic　constitutive　model,　incorporated　into　the　material　database　of　Abaqus,　is　employed　to　describe　the　mechanical　responses　of　natural　fibres.　Then,　we　implement　the　model　for　a　numerical　analysis.　The　material　parameters　of　the　model　for　the　hydrogel　matrix　and　fibres　are　determined　by　a　trial-and-error　method　from　the　experimental　curves　of　pure　hydrogel　and　fibres;　the　numerically　simulated　stress-strain　curve　of　the　composites　is　compared　with　the　experimental　one　to　verify　the　effectiveness　of　the　simulation.　Subsequently,　several　numerical　analyses　are　performed　to　discuss　the　failure　mechanism　of　hydrogel　composites　caused　by　the　microstructural　features　of　fibres.　The　findings　revealed　that　fibre　protrusion,　fibre　orientation　deviation,　and　interface　strength　significantly　affect　the　local　failure　of　the　composites　during　tensile　deformation　and　swelling;　the　composites＇　strength　and　toughness　mainly　depend　on　the　cooperation　of　various　microstructural　features.　These　results　provide　valuable　insights　into　the　design　of　fibre-hydrogel　composites.