Autogenous　laser　welding　of　5A90　Al-Li　alloy　sheets　in　a　butt-joint　configuration　was　carried　out　in　this　study.　The　microstructure　characteristics　of　the　weld　metal　and　base　metal　in　the　horizontal　surface　and　the　transverse　section　of　the　welded　joints　were　examined　quantitatively　using　electron　back　scattered　diffraction　(EBSD)　technique.　The　results　show　that　the　weld　metal　in　the　horizontal　surface　and　the　transverse　section　exhibits　similar　grain　structural　features　including　the　grain　orientations,　grain　shapes,　and　grain　sizes,　whereas　distinct　differences　in　the　texture　intensity　and　misorientation　distributions　are　observed.　However,　the　base　metal　in　the　horizontal　surface　and　the　transverse　section　of　the　joints　reveals　the　obvious　different　texture　characteristics　in　terms　of　the　grain　orientation,　grain　morphology,　predominate　texture　ingredients,　distribution　intensities　of　textures,　and　grain　boundary　misorientation　distribution,　resulting　in　the　diversity　of　the　microhardness　in　the　base　metal　and　the　softening　of　the　weld　metal.　However,　the　degree　of　the　drop　in　the　hardness　of　the　weld　metal　is　highly　correlated　to　the　microtexture　developed　in　the　base　metal.