Many of studies are conducted in friction stir welding of plat but very little in pipes, so that,this study came in friction stir welding of 6063 aluminum alloy pipe with 6082 aluminum alloy pipe to modeling and analysis this welding by finite elements method and evaluates the mechanical properties of this joint by different tests like tensile test, microstructure test, hydrostatic test, and Microhardness test. Moreover, six parameters were used during this study included rotation speed, travel speed, axial force,rotation direction,tool geometryand tilt angle. The results show the best joint was with rotation speed 1300 rpm.