The practical usage of thermoplastic polyurethane (TPU) has been significantly hindered by its well‐known tendency to pose a high fire hazard due to the release of substantial heat and toxic volatiles. Here, a binary nanostructure of B‐LDH‐C based on boron nitride (BN) nanosheets and layered double hydroxide (LDH) was fabricated as a flame‐retarded filler for TPU. Specifically, the addition of 3.0 wt% B‐LDH‐C, results in significant reductions of 44.7% in peak heat release rate, 14.6% in total heat release, and 56.5% in peak smoke production rate. In addition, the peak CO yield is reduced by 38.4%. These results indicate reduced fire toxicity. Moreover, the TG‐IR test points out the marked hindrances in combustible (hydrocarbons, esters, etc) and toxic gases (aromatic compounds, HCN). The results collectively demonstrate the high effectiveness of B‐LDH‐C in improving the fire safety of TPU, which is pertaining to the dual roles of B‐LDH‐C. The research could inspire the facile fabrication of binary structures, enhancing their potential in polymer‐matrix composites and other applications.