7003 aluminum alloy was taken as the welding object, FSW process was used for joint welding, and finite element software SYSWELD was used to simulate the welding process of aluminum alloy plate. The effects of simulation and actual welding were compared and analyzed. The results showed that when the welding speed was about 3mm/s in friction stir welding of 7003 aluminum alloy, the rotating speed of stirring head was 2 100~2 500 r/min，the welding process requirements could be met. The actual welding test results were consistent with the simulation results. The welded joints had uniform metallographic structure and properties. With solid solution at 490 ℃/3 h and manual aging at 180 ℃/12 h, the tensile strength was 369.2 MPa and elongation was 7.6% respectively after heat treatment.