Abstract: Ti-Al-Mo-V-Cr-Nb titanium alloy was tested by a thermal-mechanical physical simulation system(Gleeble-3800) at different temperatures, strain rates and a certain amount of deformation. The isothermal compression was carried out in the deformation temperature range of 760 ℃-840 ℃, strain rate range of 0.001 s^-1-1 s^-1, and deformation degree of 60%. According to the true stress-true strain curves of Ti-Al-Mo-V-Cr-Nb titanium alloy at different temperatures and strain rates, the evolution of flow stress and microstructure with deformation temperatures, strain rates were analyzed. The results show that the flow stress decreases with the decrease of strain rate and the increases of deformation temperature. The deformation thermal activation energy of titanium alloy is 218.15 kJ/mol under the condition of true strain 0.9. Using parameter Z and Arrhenius type constitutive equation, the hot deformation constitutive equation of Ti-Al-Mo-V-Cr-Nb titanium alloy is established when the true strain is 0.9. The established constitutive equation is verified, and it is found that the Arrhenius type constitutive equation constructed under experimental conditions has high accuracy, and can be used as the constitutive equation model of titanium alloy. The α phase content of Ti-Al-Mo-V-Cr-Nb titanium alloy decreases with the increase of deformation temperatures and the decreases of strain rates.