Abstract: Effect of the rotating tool figuration and welding parameters on welded bead shaping of friction stir welded 7.6 mm 7A52 aluminum alloy was investigated,and the reason causing weld defect was analyzed.The results showed that the range of the rotating tool's speed in which the weld bead could shape well was decided by the rotating tool's figuration.Furthermore,the parameters including the rotating tool's speed,welding speed,welding obliquity and shoulder pressing depth into the workpiece had very important effect on the weld bead shaping.The weld bead could shape well only when the welding parameters matched well.