The multi-step superplasticity tests of 2060 Al-Li alloy were carried out by using SANS CMT4104 tensile testing machine.The microstructure evolution and superplasticity properties of 2060 Al-Li alloy were investigated at deformation temperature of 425～500℃and prestrain of 10%to 30%.The results indicate that the elongation of the multi-step tensile specimen is increased with the increase of temperature

and increased firstly and then decreased with the increase of prestrain

which is greater than that of the single-step tensile specimen in the range of 450～500 ℃．The superplasticity is desirable when the deformation temperature is 500 ℃ and the prestrain is 20%

and the elongation reaches 211%.The interstitial insulation during multi-step tensile process leads to the decrease of flow stress

of which the degree is increased with the increase of the prestrain

and increased firstly and decreased with the increase of temperature.The peak stress at the second step tensile process is decreased significantly compared to that at single-step tensile process.The microstructure of the alloy reveals that a large number of dispersive phases appear at 425 ℃

and then dissolved into the matrix at 450 ℃ with zigzagshaped grain boundary.During 475℃to 500℃

the triangular second phase emerges in the matrix with a large number of dynamic recrystallized grains.