Abstract: Friction stir butt welding of 2 mm thick 2060 Al-Li alloy sheet was conducted. The effect of welding parameters on joint formation was investigated. The weld presented bowl shape, and consisted of shoulder-affected zone and weld nugget. The equiaxed grain in the shoulder-affected zone was bigger than that in weld nugget. At rotational speed of 800 r/min and travel speed of 80 mm/min, defect-free joint with excellent-formation surface was attained. Compared to 800 r/min of rotational speed and 80 mm/min of travel speed, increasing rotational speed or decreasing travel speed made the joint surface rougher, while decreasing rotational speed or increasing welding speed would generate tunnel defect in the weld.