Abstract: X-ray diffraction(XRD) method is used to determine the distribution of surface residual stress on the butt-welded aluminium alloy LD10 plates. Two methods of determining peak positions, i.e. half-width and parabola methods, are adopted and compared in the experiment, the distribution of residual stresses is obtained, and the distribution results of residual stresses are explained. The test shows that the results of the two methods are similar, and stress distribution curve of parabola method is largely lower than that of half-width method, which is on the low side of tensile stress and on the high side of compressive stress. At the same time, the experimental results reveal that the half-width method is better in consistency, stability, adaptability and accuracy than parabola, and the distribution data of the residual stresses surveyed by XRD method is reliable，and XRD is a valid method to measure residual stresses in welded structures. All these results contribute reference to the distribution of residual stresses on welded aluminium alloy LD10 plates.

Key words: Aluminium alloy, Butt-welding, Measurement, Residual stress, Stress distribution, X-ray