The invention belongs to the aluminum lithium alloy heat treatment technology, in particular to a heat treatment technology capable of improving the stress corrosion resisting performance of an aluminum lithium alloy. Applicable alloy components of the technology comprise main alloying elements including, by weight percent, 0.5%-5.0% of Cu, 0.4%-2.5% of Li, 0.1%-4.0 % of Mg and 0.1%-4.0% of Zn, comprise microalloying elements including any one to four of, by weight percent, 0.04%-0.02% of Zr, 0.05%-0.60% of Sc, 0.20%-0.80% of Mn and 0.1%-0.9% of Ag and comprise, by weight percent, smaller than or equal to 0.10% of Si, smaller than or equal to 0.10% of Fe, smaller than or equal to 0.10% of Ti, smaller than or equal to 0.05% of each of other impurities and the balance Al, wherein the total amount of other impurities is smaller than or equal to 0.15%. After a deformed product is subjected to annealing treatment, cold deformation of a certain deformation amount is conducted, then solution hardening is conducted, regulation and control over the recrystallization degree and the grain boundary precipitates can be achieved through the manner, and other mechanical properties of the alloy are kept unchangeable while the stress corrosion resisting performance of the alloy is improved. The alloy preparing steps include annealing treatment, cold deformation treatment, solution treatment and ageing treatment. The technology is suitable for high-performance Al-Cu-Li-X series aluminum lithium alloy thick plates and forge pieces used in the fields of aviation, spaceflight and weapons.