A　new　N–P–Cu　containing　supermolecular　assembly　network　(MPCSN)　was　fabricated　with　titanium　carbide　(Ti3C2Tx)　nanosheets　through　intermolecular　forces,　and　then,　the　flame-retardant　thermoplastic　polyurethane　(TPU)　nanocomposites　were　synthesized　by　melt　blending.　The　obtained　results　of　the　TPU/Ti3C2Tx-MPCSN　system　indicated　that　the　temperature　corresponding　to　T5%　of　TPU　nanocomposites　by　adding　2%　Ti3C2Tx　or　2%　MPCSN　decreased　to　269.1　and　311.5 °C,　respectively.　Simultaneously,　a　well　dispersion　of　the　loading　of　1.0　mass%　Ti3C2Tx-MPCSN　was　found　in　TPU　matrix.　Accordingly,　the　thermal　stability　of　TPU　can　be　found　to　be　substantially　improved　in　the　thermogravimetric　analysis,　which　was　embodied　in　the　mass　loss　of　TPU/Ti3C2Tx-MPCSN-1.0　reached　up　to　8.47　mass%.　Moreover,　the　cone　calorimeter　tests　revealed　that　the　peak　of　heat　release　rate,　the　total　heat　release,　carbon　monoxide　production　rate　and　total　carbon　monoxide　yield　of　the　TPU　nanocomposite　were　prominently　diminished　by　16.1%,　37.5%,　18.8%　and　37.6%,　respectively.　This　provides　clues　to　the　flame-retardant　mechanism　of　TPU　nanocomposites:　The　modified　Ti3C2Tx　is　combined　with　MPCSN　through　a　cross-linked　network　grown　on　the　surface　of　the　carbon　layer,　which　not　only　prevents　the　leakage　of　combustible　gas,　but　also　catalyzes　the　formation　of　the　carbon　layer.　This　work　demonstrates　a　novel design　for　improved　Ti3C2Tx　with　supramolecularly　assembled　networks　to　reduce　potential　fire　risk　in　practical　TPU　applications,　applying　to　applications　in　polymer　materials.　©　2023,　Akadémiai　Kiadó,　Budapest,　Hungary.