Isothermal compression of the TC11 titanium alloy was conducted on a Gleebe-1500D hot-simulator at the deformation temperature ranging from 960 to 1050 °C and the strain rate ranging from 0.01 to 10 s-1. The influence of deformation temperature and strain rate on the stress was studied according to true stress-true strain curves, and the constitutive equations of TC11 titanium alloy during hot deformation were established based on hyperbolic sine equations of Arrhenius type. Error analyses show that the established constitutive equations are coincident with experimental data well, and they provide a theory basis for the forging technique of TC11 titanium alloy