A　series　of　aluminum　hypophosphite　(AHPi)/graphite-like　carbon　nitride　(g-C3N4)　(designated　as　CAHPi)　hybrids　were　prepared,　followed　by　incorporation　into　thermoplastic　polyurethane　(TPU).　The　introduction　of　CAHPi　hybrids　into　TPU　led　to　a　marked　reduction　in　the　peak　of　the　heat　release　rate　(pHRR),　total　heat　release,　weight　loss　rate,　smoke　production　rate　and　total　smoke　production　(TSP).　For　instance,　pHRR　and　TSP　decreased　by　40%　and　50%　for　TPU/CAHPi20.　Furthermore,　the　increasing　fire　growth　index　and　decreasing　fire　performance　index　were　obtained　for　TPU/CAHPi　systems,　suggesting　reduced　fire　hazards.　It　was　found　that　improved　fire　safety　of　TPU　nanocomposites　was　contributed　by　condensed　phase　and　gas　phase　mechanisms.　On　one　hand,　g-C3N4　accelerated　the　thermal　decomposition　of　AHPi　for　the　formation　of　more　char　layers.　On　the　other　hand,　g-C3N4　induced　AHPi　to　generate　more　free　radical　capture　agents　when　exposed　to　flame,　besides　protecting　AHPi　against　thermal　oxidation.　©　2017　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.