Promising　cotton　fabric　composites　are　designed　to　beprotectedby　flame　retardant　thermoplastic　polyurethane　(TPU)　composites　forthe　next-generation　fire-proof　suit.　Herein,　we　successfully　constructedflexible　cotton/TPU　hierarchical　composites,　where　a　comfortable　cottoninternal　layer　was　obtained　by　multiple　dip　coating　of　titanium　carbide(MXene)　and　ammonium　polyphosphate　(APP)/TPU　composites　served　asexternal　layers.　The　flame　retardant　and　mechanical　properties　ofits　cotton/TPU　hierarchical　composites　were　tuned　by　adjusting　thedip　coating　circle.　The　obtained　thermogravimetric　analysis　resultsof　the　TPU/APP/Cn　system　indicated　that　the　char　residue　of　MXene-basedcotton/TPU　hierarchical　composites　by　third　dip　coating　increasedfrom　9.81　to　30.81　wt　%.　Notably,　the　hierarchical　composites　showed87.2%　and　65%　reductions　in　the　peak　of　heat　release　rate　and　totalheat　release,　respectively,　compared　to　pure　TPU.　Besides,　their　mechanicalperformance　was　improved　significantly,　e.g.　the　tensile　strength,elongation　at　break,　and　toughness　reaching　20　MPa,　400%,　and　30.0MJ/m(3),　respectively.　These　properties　improvements　aredue　to　the　synergistic　effect　between　MXene-based　cotton　and　TPU/APPcomposites.　This　work　offers　a　promising　attempt　for　the　design　offlexible　and　multifunctional　cotton/polymer　hierarchical　compositeswith　brilliant　flame　retardancy　and　mechanical　properties.