Al-Cu-Li-X alloy has attractive applications in the aerospace and aeronautic industry due to its excellent combination of mechanical properties and corrosion resisting properties. However, the microstructural complexity, especially the type and distribution of precipitates have effects on the properties. Besides changing the chemical compositions of alloy, the preaged stretch after quenched and aging process is the main method to control the type and distribution of precipitates. In this work, the effect of preaged stretch after quenched on tensile properties, corrosion property, aging response and microstructure of a naturally aged Al-Li alloy were studied by DSC, TEM, tensile test and corrosion test. The results show that the yield strength increases gradually at the stretch range from 0 to 6%, ultimate tensile strength decreases with the increase of stretch from 0 to 3%, and then become stable when stretch over 3%. Accompany with the increasing stretch, the corrosion type of alloy changes from intergranular corrosion to point corrosion. The T34 state of alloy has the least corrosion depth, about 0.03 mm. The aging response character of alloy is changed by preaged stretch. Compared with T4 state, the endothermic peak near 100 ℃ move to higher temperature, and two exothermic peaks near 180 ℃ and 260 ℃ move to lower temperature in T3x state, respectively. Preaged stretch after quenched restrains the precipitation of δ’ phase in grain and grain boundary with increasing the density of dislocation in grains. The variations of δ’ phase and dislocation affect the tensile and corrosion properties of alloy.