Abstract: Aluminum hypophosphite (AHP) and melamine cyanurate (MCA) were adopted as flame retardants to prepare a series of flame retardant thermoplastic polyurethane elastomer composites (FR-TPU) by a melt blending method. The thermal stability, flame retardant performance, combustion properties, mechanical properties and char morphology of the resulting FR-TPU were investigated by means of thermogravimetric analysis, limiting oxygen index (LOI) test, UL 94 vertical burning experiment, cone calorimetry, mechanical measurements and scanning electron microscopy. The results indicated that the combination of AHP and MCA could enhance the flame retardancy of TPU, and the FR-TPU containing 20 wt.% of AHP-MCA achieved a LOI of 30.5 vol.% as well as a UL 94 V-0 classification in the vertical burning test, and its peak heat release rate and total heat release were reduced to 436 kW/m2 and 55.5 MJ/m2, respectively. Moreover, the FR-TPU presented the tensile strength of 25.45 MPa and elongation at break of 588.3 %. Morphological observation demonstrated that the combination of AHP and MCA significantly enhanced the compactness of residual char for FR-TPU. In this case, the compact char layer could effectively inhibit the mass and heat transfer of combustion area, thus enhancing the fire safety of the composites.