Abstract: Fracture property of different regions of 2219 aluminum alloy friction stir welds was studied in terms of crack tip opening dispacement (CTOD).Three-point bending specimens were used to measure the fracture toughness of various regions of 2219 aluminum alloy friction stir welds.CTOD values were calculated according to p-s curves obtained.Results show that the fracture of 2219 aluminum alloy friction stir weld is ductile and the distribution of fracture toughness is heterogeneous;the fracture toughness of weld nugget is the best following thermal-mechanical affected zone and heat affected zone,and base material is the weakest.