Taking Ti-575 titanium alloy as the research object, the thermal mechanical compression experiments were conducted on both lamellar structure and bimodal structure Ti-575 titanium alloys. The true stress-strain curves under different thermal deformation conditions were analyzed, the constitutive equation for hot deformation in the α+β phase region was established, and the influence of the deformation temperature and strain rate on the microstructure was nvestigated. The results show that the flow stress decreases with increasing deformation temperature and increases with increasing strain rate. When the strain rate is 0.1 s -1 or higher, the flow curve exhibits discontinuous yielding with increasing deformation temperature. Based on the peak stress of the flow curves of the two types of Ti-575 titanium alloys, the deformation activation energy in the α+β phase region is calculated, and an Arrhenius-type constitutive equation for hot deformation is established. Under different thermal deformation conditions, with increasing deformation temperature, the degree of dynamic recrystallization in the lamellar structure Ti-575 titanium alloy increases, while the volume fraction and size of equiaxed α p phase in the bimodal structure Ti-575 titanium alloy gradually decrease. With decreasing strain rate, the degree of dynamic recrystallization in the lamellar structure Ti-575 titanium alloy gradually increases, while the volume fraction of equiaxed α p phase in the bimodal structure Ti-575 titanium alloy first decreases and then increases. When the bimodal structure Ti-575 titanium alloy is hot compressed at a temperature of 830 ℃ or a strain rate of 1 s -1 , a small amount of coarse lamellar α phase remains unchanged in the microstructure, and silicide precipitates in the β t matrix.