In the paper, AZ31B magnesium alloy/DC56D steel dissimilar metal incompatible metals are welded using magnetic pulse welding. We have comparatively studied the effect of Primary and Secondary welding on the welded interface. Macroscopic morphology, microstructure, and interfacial structure have been analyzed using techniques such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results show that magnetic pulse welding of Mg/Fe dissimilar incompatible metals is realized using Al interlayer as a bridge of deformation and diffusion. The studies display that the AZ31B/Al1060 interface appears the typically wavy interface, a transition zone exists in the joint interface and may cause extremely complex microstructure. The transition zone structure differs from AZ31B Magnesium and 1060 Al alloys, which could be brittle intermetallic compounds of Al3Mg2 and Al12Mg17. The transition zone is mainly on the Al side, with a maximum thickness of about 13.53μm in the Al transition layer. We observed incomplete melting layers of varying thicknesses at the Primary weld interface and micron-sized hole defects in the transition zone of the Secondary weld interface. Al1060/DC56D interlayer is mainly straight in shape, with only a small number of transition zones in the joint interface distributed intermittently across the interface, and the transition zone is characterized by the presence of FeAl3 brittle intermetallic compounds, with a maximum thickness of about 2.43 μm.