The phase transition and grain refinement features of a Ti-6Al-4V alloy are investigated in this study using in-situ high- temperature Electron Backscatter Diffraction (EBSD). The objective of the experiment was to detect the phase transition from Body-Centered Cubic (BCC) to Face-Centered Cubic (FCC) systems at temperatures ranging from 770 to 900 degrees Celsius. Grain refinement techniques such as recrystallization twin generation, Kernel Average Misorientation (KAM), and low-angle grain boundary creation were the focus of this study. According to our research, phase transformation maps taken at 770°C, 810°C, 840°C, and 900°C reveal that a discontinuous recrystallization process was responsible for the transformation and recrystallization. The results of this investigation provide support to the theory that high-temperature treatments may enhance the microstructure of additively made Ti-6Al-4V alloys. At temperatures of 900 °C, the grain structure was evenly polished, and an almost complete phase shift to a face-centered cubic (FCC) shape was observed.