Titanium alloys are critical structural materials with excellent comprehensive properties such as high specific strength, low density, and high corrosion resistance. These properties of titanium alloys can be tuned by the manipulation of microstructure evolution during a variety of heat treatment. In this work, we used advanced scanning electron microscopy, transition electron microscopy and MIPAR image analysis software to quantitatively study the microstructural evolution during the post-heat treatment for the direct energy deposited (DEDed) Ti-5Al-5V-5Mo-3Cr (wt.%, Ti-5553) alloy. The influence of heating rates, aging temperature, and cooling rates on the ⍺ microstructure during post heat treatment were systematically investigated. Refined, more-refined, and super-refined ⍺ microstructure with different number densities and microhardness were successfully generated. We will introduce the critical roles of post heat treatment on fine-tuning the ⍺ microstructure in the DEDed Ti-5553. This work is supported by the National Science Foundation, grant CMMI-2122272.