The flow behaviors and microstructural evolutions during multi-stage hot deformation are essential aspects in the processing of high performance titanium alloys. In the present work, both isothermal multi-stage deformation (IMD) and non-isothermal multi-stage deformation (NMD) over α + β and single β phase regions were employed to study the constitutive behaviors and microstructural evolutions of a near-α Ti-5Al-2.5Sn alloy. The results showed that the flow stress, restoration fraction in α + β phase region of NMD were lower than that of IMD, because that the predominant lamellar microstructures formed during NMD increased α/β boundaries and thereby promoted grain boundaries gliding. In β phase region, the flow behaviors showed slight differences with temperature and deformation passes during both IMD and NMD processes. Clear transitions were observed from the mean flow stress between different phase regions during NMD. In addition, an obvious α + β→β dynamic phase transformation occurred during deformation at 990 °C, which was identified to be a displacive nucleation and diffusion-controlled growth process. In addition, numerous FCC-Ti precipitations were observed during IMD at 960 °C and strain rate of 1 s⁻¹ with the orientation relationship of (0 0 0 1)_{HCP matrix} //{1 1 1}_FCC.