The　integration　of　high　strength,　high　toughness,　and　excellent　flame　retardancy　in　polymer　materials　is　highly　desirable　for　their　practical　applications　in　the　industry.　However,　existing　material　design　strategies　often　fail　to　realize　such　a　performance　portfolio　because　of　mutually　exclusive　mechanisms　between　strength　and　toughness,　and　low　flame　retardancy　efficiency　of　nanofillers　in　polymers.　Here,　we　reported　the　preparation　of　a　multifunctional　nanohybrid,　Ti3C2Tx@MCA,　by　engineering　the　surface　of　titanium　carbide　nanosheets　(Ti3C2Tx,　MXene)　with　melamine　cyanurate　(MCA)　via　hydrogen　bonding　interactions,　and　subsequent　thermoplastic　polyurethane　(TPU)/Ti3C2Tx@MCA　nanocomposites.　The　resultant　TPU　nanocomposite　containing　3.0　wt%　of　Ti3C2Tx@MCA　shows　a　high　tensile　strength　of　61.5　MPa,　a　toughness　as　high　as　175.4　±　7.9　MJ　m−3　and　a　high　strain　at　failure　of　588%,　and　40%　reduction　in　the　peak　of　heat　release　rate.　Such　extraordinary　mechanical　and　fire　retardant　performances　are　superior　to　those　of　its　previous　counterparts.　Interfacial　hydrogen　bonding　in　combination　with　the　“labyrinth”　effect　and　catalytic　action　of　2D　Ti3C2Tx　nanosheets　are　responsible　for　the　outstanding　mechanical　and　fire　retardancy　properties　of　TPU　nanocomposites.　This　work　provides　a　new　paradigm　for　integral　design　of　high-performance　polymeric　materials　with　excellent　mechanical　and　fire-safe　performances　portfolio.　©　2020　Elsevier　B.V.