Abstract: The tensile simulation was carried out on 6063 aluminum alloy welded joint with different weld strength matches with software ABAQUS, and the influence of weld strength matchon the distribution of stress triaxiality in aluminum alloy welded joint was studied. At the same time, the influence of HAZ width on the distribution of stress triaxiality in welded joint was studied in each strength match condition. The results indicate that the stress state in welded joints with different weld strength matches was complicated, compared to the base material. Bounce in the stress traxiality existed in the boundary between the base material and HAZ and between the weld and HAZ. The maximum of stress traxiality in high strength match welded joint was the largest. On the contrary, the maximum of stress traxiality in low strength match welded joint was the least. Under the condition of equal strength match, the position of the maximal stress traxiality changed from the boundary between the base material and HAZ to the boundary between the weld and HAZ with the increasing of the width of HAZ. Under the condition of high strength match, the maximum of stress traxiality appeared in the boundary between the weld and HAZ, and the maximum of stress traxiality reduced gradually with the increasing of the width of HAZ. However, under the condition of low strength match, the maximum of stress traxiality appeared in the boundary between the base material and HAZ, and the maximum of stress traxiality also reduced gradually with the increasing of the width of HAZ.