Abstract: Aluminum extrusions were widely used in rolling stock,automobile and aerospace, et al.In this paper,based on friction stir welding(FSW) technology and equipment for aluminum extrusions,impact properties,plastic deformation capacity and microstructure of 6063-T651 FSW weld were studied.The results showed that there were fine dynamic recrystallized grain in FSW weld,precipitation was dispersedly distributed,and impact properties and plastic deformation capacity of the weld was approximately the same with that of the base material.