The effect of laser remelting (LR) on the microstructure property and thermal stability of Ti-6Al-4V alloy prepared by laser powder bed fusion (LPBF) was investigated. The results show that after LR treatment, the thermal stability of the α′ phase within the LRed-Ti-6Al-4V titanium alloy samples is significantly improved, and the temperature at which β-Ti phase appears is up from 500 ℃ to 700 ℃. After heat treatment, the grains in LPBF-Ti-6Al-4V titanium alloy grow continuously, and obviously appear to be “short bar-like” and “coarse lamellar” at the temperature above 700 ℃; while the grains in the melting zone of the surface layer of the LRed-Ti-6Al-4V sample are still maintain equiaxial, and the relatively uniform and fine needle-like microstructure are observed in the melting zone and heat affected zone above 700 ℃. The surface microhardness of those two groups of samples decreases with the increased temperature, especially significant at 700 ℃ and 850 ℃ respectively. It is found that the rapid coarsening of β-Ti grains is the main reason for the falling down of hardness.