Deformation behavior of a commercial TC6 titanium alloy at elevated temperature has been investigated using isothermal tension tests. By SEM, the fracture mechanism has been analyzed through the morphologies of failure surface. The superplasticity of the TC6 titanium alloy improves with an increase of deformation temperature and a decrease of initial strain rate. The optimal process parameters are the combination of 950 degrees c and 0.001s(-1), and the limit elongation could reach 267%. The tough fracture is main pattern in the failure of the TC6 titanium alloy. The fracture begins at the boundaries between the matrix and the impurity, and it presents the much more tough fracture characteristic with an increase of deformation temperature and a decrease of initial strain rate.