With Nb-Ti-Al-based low-density niobium alloy subjected to heat treatment under different high temperature conditions, the samples coated with the alloy are melted at a high temperature of 1 300℃for 30 minutes. By using INSTRON4505 universal testing machines, metallographic microscopes, scanning electron microscopes, and energy spectrum analyzers, a comparative analysis has been made of the mechanical properties (with a tensil strength of /бb, a yield strength of /б0.2 and elongation), metallographic structure, and fracture morphology of the heat-treated sample at room temperature (25℃). The results show that for every 100℃increase in the melting temperature (t≥900 ℃), the tensile strength decreases by 9.23%, the yield strength decreases by 9.11%, the elongation decreases by 9.59%, while the proportion of grain size increases by 21.43%. With the melting temperature reaching higher than 1 200℃, the sample experiences a fracture by only measuring the tensile strength value, showing that with an increase of the melting temperature gradient, the mechanical properties of the sample substrate decrease correspondingly, the grain size and hardness increase continuously, while the plasticity and toughness decrease continuously as well.