<p>2050 Al-Li alloy has been widely used in aerospace and marine industry because of its advantages such as light weight, but its corrosion failure has limited its use to a certain extent, so the study of the corrosion mechanism of the alloy is particularly important. In this paper, the mechanism of intergranular corrosion (IGC) of 2050 Al-Li alloy was studied through electron backscattering diffraction (EBSD) by changing the pre-deformation direction (0°, 30°, 60° and 90°). It is found that the grain size changes obviously by changing the pre-deformation direction, and the IGC rate will be accelerated when the grain size is reduced. In the study of grain orientation, it is found that the atomic arrangement density of different orientation crystal faces will also affect the IGC properties. The higher the atomic arrangement density of the crystal surface, the better the corrosion performance. Therefore, the crystal grain orientations of the alloy, in order from smallest to largest IGC rate, are (111), (101) and (001). In addition, it is found that the grain misorientation also has a direct effect on the IGC properties. The smaller the misorientation, the better the corrosion performance.</p>