This work presents a systematic approach to addition welded joints of 6061 aluminum pipefabricated by friction stir welding of pipes has been investigated. 5%, 10%, 15% and 20% Aluminum Oxide (Al2O3) powder was added to weld interface. Welding was performed on the pipe with different material thickness 2 to 4mm, rotational speeds 1800 RPM and a traverse speed 4 mm/min was applied. The Mechanical properties of welded joints were investigated using different mechanical tests, including nondestructive test (visual inspection) and destructive test (tensile strength and hardness). This paper presents indicated that the addition percentage of added material has a major effect on the mechanical properties of friction stir welding ofpipes joint. The results have been obtained at 20% Aluminum Oxide (Al2O3) powder at the weld interface.