Abstract: Thermoplastic polyurethane elastomer (TPU) was equipped with excellent properties, which was widely used in various fields of industry and living. However, the application scope of TPU was limited because the material was a kind of organic polymer material with high inflammability. Moreover, a large amount of CO, CO₂, NO_x and other toxic asphyxiating gases from TPU material were released during combustion. The design of MXene-based hybrid flame retardant based on layered titanium carbide (Ti₃C₂T_x) and manganese dioxide (MnO₂) was proposed for preparation of MXene-based hybrid/TPU nanocomposites. The mechanisms of flame retardancy, smoke suppression and toxicity reduction of the TPU nanocomposites were studied by means of TGA, XRD, SEM and other techniques. In the case of Ti₃C₂T_x-MnO₂/TPU systems, the total heat release (THR), the total smoke release (TSR), the total CO yield (CO TY) and the total CO₂ yield (CO₂ TY) of the TPU nanocomposite were maximally decreased by 28.62%, 33.41%, 34.12% and 29.77% respectively compared to those of TPU, besides 91.89% increase in residual char at 700℃. According to the analysis, Ti₃C₂T_x in MXene-based hybrid flame retardant was oxidized to TiO₂ and co-catalyzed with MnO₂ to form carbon, which not only improved the continuity and compactness of carbon layer after combustion of nanocomposite materials, but also blocked the entry of heat and oxygen and inhibit the release of flue gas.