Thermo-plasticity of homogenized 7050 aluminum ingot was investigated by instantaneous tensile tests conducted at different temperatures.The results show that,with the increase of testing temperatures,the strength decreases,and the plasticity increases firstly and then decreases in homogenized 7050 ingot.When the studied alloy is deformed between 380 ℃ and 420 ℃,the deformation resistance is lower and plasticity is better.And the actual heating temperature for ingot before hot extrusion should becontrolled between 360 ℃ and 400 ℃.At low tensile temperatures,the deformation structure is mainly composed of dislocation substructure.With the increase of testing temperatures,transgranular fracture transforms into intergranular fracture progressively during deformation.At high tensile temperatures,the grain boundaries are weakened,deformation is concentrated at the grain boundaries and the re-orientation of equilibrium phases at grain boundaries appears.