Abstract: In order to further improve the performance of Aluminum alloy welded joints, the effect of alternating magnetic field-assisted CMT welding technology on the weld formation, microstructure and performance of 6061 Aluminum alloy joints is investigated. The results show that the application of alternating magnetic field can obtain good weld formation, and can significantly reduce the size of the joint porosity area and porosity. Without magnetic field, the weld structure mainly consists of columnar dendrites and equiaxed dendrites, but after the application of alternating magnetic field, the columnar dendrites are broken into equiaxed dendrites and the grain refinement is obvious, and the average hardness of the weld is 77.10 HV, which is 21.63% higher than that of the weld without the application of magnetic field. The elemental content of the white area of the weld was detected by EDS, and it was found that the content of each element did not change much with or without the magnetic field, and it could be inferred that this area was an Al-Si eutectic precipitation phase, which was mainly distributed along the α-Al grain boundaries. The tensile strength of the joint does not change much under different magnetic field parameters, and there is a softening zone in the heat-affected zone, and the fracture location is also in this region, and the type of fracture belongs to toughness fracture. Electrochemical corrosion is carried out in the welded joint area, and the results of AC impedance and kinetic potential polarization curves show that the welded joints have better corrosion resistance after the addition of alternating magnetic field assistance.