Advanced　aircrafts　have　incorporated　bio-inspired　morphing　structures　to　adapt　to　multienvironment　and　perform　multimission.　But　it　will　cause　serious　issues　with　structural　reliability　and　aeroelastic　stability.　This　paper　studies　the　critical　flutter　speed　of　a　morphing　wing　structure　and　evaluates　the　deformation　strategies.　First,　a　biomimetic　wing　is　considered　as　a　variable　cross-section　cantilever　beam,　and　the　flutter　model　with　Theodorsen　unsteady　aerodynamics　is　theoretically　derived.　The　finite　element　theory　is　used　to　discretize　the　obtained　PDEs　with　variable　coefficients.　Second,　three　typical　wing　models　are　examined　to　verify　the　model＇s　accuracy　against　finite　element　simulation　findings　for　modal　frequencies　and　critical　flutter　speeds.　The　results　indicate　good　agreement,　with　errors　of　less　than　3%　for　modal　frequencies　and　fewer　than　2.1%　for　critical　flutter　speeds.　Thirdly,　the　flutter　wind　speeds　are　examined　to　assess　the　aeroelasticity　properties　for　three　different　morphing　strategies　of　biomimetic　wing　structures.　The　findings　show　that　both　forward　bending　of　the　elastic　axis　and　greater　density　concentration　near　the　wing　root　increase　flutter　speed.　And　the　density　distribution　has　a　smaller　effect　on　flutter　speed　than　elastic　axis　bending.　When　it　comes　to　static　aeroelasticity,　excessive　folding　ratios　cause　divergence　problems.