The deformation mechanism and microstructure evolution of TLM titanium alloy were studied during cold compression at room temperature and hot compression at 850 oC under the condition of 0.001 s-1 strain rate. The results show that the deformation mechanisms and microstructure evolution under cold and hot compressions of TLM alloy are different. Twinning, stress-induced α" phase transformations and dislocations slipping are the main deformation feature in cold compression, whereas the dislocations slipping, dynamic recovery (DR) and dynamic recrystallization (DRX) are the main deformation mechanisms in hot compression. The stress flow softening of TLM alloy in hot compression is related to DR and DRX. Meanwhile, the compressive strengths in cold and hot compression are 975 and 40 MPa, respectively. Compared with the cold compression, the compressive strength of hot compression is decreased by about 96%