The hot deformation behavior of Ti-6Al-4V-0.1Ru titanium alloy was investigated by isothermal compression on Gleeble-3500 thermal simulator under the conditions of deformation temperature ranging from 800℃ to 1100℃ and strain rate ranging from 0.01 s^-1 to 10 s^-1. The results revealed that the peak stress of Ti-6Al-4V-0.1Ru titanium alloy increased with decreasing the deformation temperature and increasing the strain rate, the softening mechanism was dynamic recovery below 950℃ and dynamic recrystallization above 950℃. The constitutive equation of Ti-6Al-4V-0.1Ru alloy was calculated by a linear regression analysis in two phase regions in the form of Arrhenius-type relationships. It is found that the apparent activation energies were calculated to be 720.477 kJ/mol and strain rate sensitivity index was 4.809. By introducing the influence of strain on the material constants of α, n, A and Q, the fixed constitutive model of flow stress was established, through comparing the experimental and predicted results, the correlation coefficient reached 96.9%, it was illustrated that this constitutive model had better prediction precision.