Abstract: Friction stir welding parameters play an important role of figuration and mechanical properties of welded joint.In this study, the 3 mm plate of 2024 aluminum alloy was selected as base metal.By operating a great deal of butt welding experiments, the quality of welded joint under various parameters was tested.Furthermore, the welding parameters window was established.In the parameter of rotation speed 375-475 r min and welding speed 150-235 mm min, the tensile strength of welded joint can be higher than 80% of the one of base metal.By analyzing the tensile fracture, at the upper district of joint, the material had good plastic aspect, while the lower district was worse than the upper one.The joint showed distinct layers along the depth.