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.