Abstract: The β-grain growth of TB6 titanium alloy heated at β-phase region was studied, and the β-grain growth activation energy was calculated. The β-grains sizes evolution model was also developed in this paper. The results show that the β-grain size increases fast and then slowly with the increasing of the holding time, presenting a power function relationship between the β-grain size and the holding time. With the increasing of the heating temperature, the β-grain size slowly increases at first, then rapidly increases when the heating temperature is over 940℃, presenting an exponential relationship between the β-grain size and the heating temperature. The β-grain growth activation energy was calculated to be 92.77 kJ/mol, and a β-grains sizes evolution model with an error of 8.9% between calculated values and the experimental data was developed.