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The hot deformation behaviors of a new type high strength and toughness TB17 titanium alloy was investigated on the thermo mechanical simulator (Gleeble3800). The experiment conducted at temperatures ranging from 775 °C to 905 °C and strain rates various from 0.001 s?1 to 1 s?1. The softening mechanism of flow stress and microstructure were investigated during hot deformation process and the Arrhenius type constitutive equation were established as well. The stress of TB17 titanium alloy varies with sensitivity of the strain rate at defferent deformation temperatures. Duing deforming at α+β field，the peak stress was sensitive to low strain rates，while at β field deforming，the peak stress was sensitive to high strain rates. The strain rate has a major impact on the microstructure of TB17 titanium alloy. The dynamic recovery mechanisms plays an dominant role as the strain rate exceeds 0.1s-1. Dynamic recrystallization plays an significant role while the strain rate is in the range of 0.001 s-1~0.1s-1. Recrystallization processing can be promoted with the decreasing of strain rate. The microstructure of equiaxed grains with a size of 25μm was obtained with a strain rate of 0.001 s-1. The temperature also has great influence on the dynamic recrystallization. During deformed at α+β field lead to primary α phase recrystallization, while at β field lead to the β grain recrystallization. The activation energy for hot deformation below and above the temperature of phase transformation point is 538.4KJ/mol and 397.4KJ/mol, respectively. The softening mechanism of hot deformation temperature ranged from 775 to 905℃ transformation point is grain boundary glide.