Abstract: Hot deformation behavior of commercial pure titanium TA1 was investigated in temperature range of 750-950 ℃and strain rate range of 0.01-10 s^-1with the maximal deformation of 50% by using Gleeble simulator. The results show that the flow stress decreases with the increase of deformation temperature, and increases with the increase of strain rate.When the material is deformed below the β phase transition point, the main softening mechanism is dynamic recrystallization,and the grain size decreases with the increase of strain rate and the decrease of temperature. While the material is deformed above the β phase transition point, the main softening mechanism at low strain rate is dynamic recovery. With the increase of strain rate, the dynamic recrystallization softening effect is enhanced. The grain refinement effect is better deformed at 750 ℃ with a strain rate of 1 s^-1and 10 s^-1. At low strain rate and high deformation temperature, lamellar and coarse α phase grains appear, and the grain refinement effect is bad. The Arrhenius constitutive equation of commercially pure titanium TA1 is established based on strain compensation. The relationship between constants α, n, Q, lnA and strain ε can be expressed by a 5-order polynomial fitting.