Abstract: The vacuum annealing process was used to perform intermediate annealing treatment for the aluminum alloy wire after each pass drawing during drawing process. The prepared ER5356 aluminum alloy wire was used to weld 7A52aluminum alloy plate with a thickness of 20 mm by the MIG welding method, and the microstructure and properties of the joints were analyzed and studied. The results show that the weld quality of ER5356 aluminum alloy wire prepared by vacuum intermediate annealing process reaches level I. Compared with those of the wire prepared by atmospheric intermediate annealing, the weld structure and grain size have little change. The mechanical properties of the welding joint of the welding wire prepared by vacuum intermediate annealing are better than those of welding wire prepared by atmospheric intermediate annealing, the average tensile strength of the joint is 293MPa, the average elongation after fracture is 5.5%. The tensile fracture mechanism of the joint is ductile fracture.