In order to study the super-plastic parameters of high temperature titanium alloy TA12A, the high temperature tensile tests with 2 mm thick plates were carried out under different temperatures and initial strain rates, the microstructure of specimen was studied at 920 ℃. The results show that  the total elongation rates of TA12A sheet are all above 400% at 900-940 ℃ and good super-plastic tensile properties are obtaind. Elongation rate of 785% is obtained at 940 ℃ under the initial strain rate of 1×10-3 s-1. Considering that the higher temperature leads to longer keeping time and more obvious reduction of the material properties after forming in actual production process, the final process parameters are determined as temperature 920 ℃ and initial strain rate 1×10-3 s-1. The grain size growth of stretch part is affected by both holding time and stain during super-plastic deformation.