2219 aluminum alloys with dissimilar heat treatment were butt welded respectively by conventional and weaving tungsten inert gas arc welding. The characteristics of mechanical properties , microstructures and hardness distribution of the joints were studied. The analysis results showed that compared with conventional welding process joints, the weaving welding joints’ mechanical properties improved while the micro hardness values decreased in bottom region of PMZ and OAZ, and the width range increased. The joints strain distribution showed that conventional welding process joints’ max strain distribute along diagonal while the weaving joints show like nearly “W” form before fracture occurred. The microstructures observation showed that the quantity and size of the continuous second phase decreased in weaving welding joints’ CYS side PMZ and OAZ meanwhile, the fracture surface were ductile fracture mostly among the mixed fracture mode.