Abstract: Compression tests were conducted with as-cast Ti45A18Nb2Mn0.2B alloy at strain rates of 1-10^-3/ s at temperatures of 900-1200℃. Deformation processing and microstructure changes were analyzed. It is found that the strain-rate-sensitivity coefficients range from 0.10 to 0.24 at the test temperatures. The true stress-true strain curve shows a peak stress, then the flow stress decreases into a steady value with the increase in stain. Dynamic re-crystallization occurs in the alloy during the high-temperature deformation and considerable microstructure refinement is achieved. The recrystallized grain size decreases with the decreasing of compression temperature and the increasing of strain rate, that is, with the increase of Zener-Hollomon parameter. Recrystallization processing can be promoted with the increasing of temperature and the decreasing of strain rate.