Abstract: FSW 6056-T6 Al alloy panel was welded by FSW and its distortion was measured.Also numerical model was established to simulate the distortion, temperature field and stress fields. The simulated temperature and distortion were compared with those of experiments.The results indicated that the panel bent down along welding direction and maximum distortion reaches 6.3 mm.Along the transverse direction, the panel bent up relatively to the longitudinal sides and the maximum displacement was 4.5 mm.There were high accordance trends of simulated distortion to the experiment.The longitudinal residual stress was asymmetric with the weld center line and it is higher on advancing side.