In the current study friction stir welding of two combination of alloys AA7475-AA8011 and AA8011-AZ31 B is conducted. The influence of tool performance of these two-alloy combination using various tool pin profile based on mechanical properties and microstructural evaluation are also investigated in this study. The process capacity index analysis and interval plot analysis were used to determine the best material combination. Taguchi's design approach was used to determine optimal rotating speed and welding speed. The process capacity index analysis suggests that AA7475-AA8011 welds have superior characteristics than AA8011 – AZ31 B. The AA7475-AA8011 welds produced by taper with threaded tool pin showed better mechanical properties. Taguchi optimization reveals that welding speed is the most major factor influencing all outcomes. The optimal process parameters for the best GA outcomes for combined function are TH, rotating speed 2000 rpm, and welding speed 23.43 mm/min.