Abstract: A finite element model of 7005 aluminum alloy weldment was established to simulate and analyze the redistribution of residual stress in the compact tensile specimen (CT specimen) extracted from the plate. The results show that when the notch of the CT specimen is in the weld center line, the transverse residual stress is compressed at both ends of the centerline, the middle is in the tensile state, and the longitudinal residual stress is in the compressed state, while when the notch is opened in the weld toe, the transverse residual stress is compressed at both ends, the middle is in the tensile state, and the longitudinal residual stress is in the tensile state. When the notch is in the base metal, the transverse residual stress is in the tensile state at both ends, the compression state in the middle, and the tensile state in the longitudinal residual stress. Further analysis shows that when the distance between the center line of the weld and the edge of the CT specimen exceeds the width of the specimen 1/4, the transverse residual stress at both ends is compressed and the middle is tensile, otherwise it shows the opposite rule. The longitudinal residual stress in the center of the weld decreases with the decrease of the width of the base metal. With the help of the 3-Bar model, it is found that when the width of the base metal on one side of the weld is less than 59 mm, the residual stress in the center line of the weld is compressed.