Abstract: Superplasticity of Ti80 alloy is investigated after thermal cycling deformation at temperature below 930℃.The result shows that the strain rate sensitivity(m) of the alloy is more than 0.3 at trmperature from 800 to 980℃ and the elongation is 350% at the highest temperature of test 930℃ with tensile rate of 0.2mm/min after 5 cycles.The grain is refined firstly and then grow up during deformation.The structure is homogeneous and the grain keeps equiaxed after deformation.Ti80 alloy exhibits superplastic properties.