Abstract: Flow stress and microstructure evoluation of TC1 titanium alloy at high temperatures ranging from 650 ℃ to 750 ℃, and strain rates from 0.000 5 s-1 to 0.01 s-1 through tensile test. Constitute equation at high temeperature were obtained based on the revised Hooke law and Grosman equations. The results show that the flow stress decreased rapidly at first with the increase of temperature, and then decreased slowly when temperature up to 700 ℃ at constant strains rate. When deformation temperature was constant, flow stress increased with the increase of strain rate. When TC1 titanium alloy deformed at 700 ℃, low strain rate could contribute to the occurrence of dynamic recrystallization. The constitutive equation obtained according to experimental data could accurately reflect the flow behavior of TC1 titanium alloy at high temperature.