In this paper，the in-plane anisotropy of super high-strength 2A55 Al-Li alloy sheets with thicknesses of 10 mm and 2 mm were compared and analyzed by means of tensile test at room temperature， X-ray and EBSD texture detection，etc.The effects of different heat treatments and grain structures were studied. The results show that the hard orientations were parallel to the rolling direction （0°） and the transverse direction （90°） after heat treatments. The anisotropic behavior of the sheets can be mainly attributed to the crystallographic texture， because the calculated Taylor factors were consistent with the yield strength anisotropy of the solutionized sheets and the sheets in condition T6. The severer anisotropy of 10 mm-thickness sheets was attributed to higher volume fraction of textures and aspect ratio of grains.Moreover， the aging treatments weakened the anisotropy of 10 mm-thickness sheets， but it had an opposite effect on 2 mm-thickness sheets. Sheets in condition T3 and T8 displayed severer in-plane anisotropy than those in condition T4 and T6. The pre-deformation before aging treatments increased the anisotropic behavior of the sheets.