Abstract: Due to the increasing stiffness requirements in the aerospace industry and the military, there has been a great interest in high lithium-containing aluminium alloys (>2%). Adequate optimization of the microstructure of aluminium-lithium alloys is of great value in improving the overall performance of high-lithium alloy plates for applications in the aerospace industry. In this paper, the effects of Li and Sc content on the microstructure and mechanical properties of aluminium-lithium alloys under different aging processes were investigated by analytical techniques such as metallurgical microscopy (OM), electron backscattering diffraction (EBSD), and transmission electron microscopy (TEM). The experimental results show that Sc can refine the grains and improve the hardness of Al-Li alloys. A large number of weaves exist in Al-Li alloys with different compositions, among which the Al-5% Li-0.1% Sc alloy has Brass011 <211> weave, Cube001 <100> weave and 30° ND Cube weave on 111. In addition, Al₃(Li, Sc) has a good co-lattice relationship with the matrix. It firmly pinches the dislocations, resulting in an increase in the dislocation density and thus an increase in the hardness of the alloy.