Abstract: High temperature tensile test of Ti2AlNb alloy was carried out at different temperatures between 750 and 950 ℃ and at different strain rates between 0.1 and 0.001 s-1. The influences of temperature and strain rate on the tensile strength and percentage elongation of the alloy were also studied, and then the stress-strain constitutive model of the alloy under the condition of high temperature deformation was established. The results show that the Ti2AlNb alloy was a kind of temperature sensitive and strain rate sensitive material. With the increase of the deformation temperature or decrease of the stain rate, the tensile strength of the alloy decreased and percentage elongation increased. The heat forming constitutive model of Ti2AlNb alloy was established based on the modified Hooke′s law and Grosman correction equation. The calculated flow curve of the model matched the experimental curve well, indicating that the constitutive model can be used to characterize the deformation behavior of the alloy.