Abstract: The diffusion bonding of AZ31B magnesium alloy and 7075 aluminum alloy with Zn as the intermediate layer was achieved by using the assisted pulsed current-based TLP diffusion bonding technology. The influence of diverse surface treatment methods and processing parameters on the strength of the joints was investigated. The microstructure and morphology of the joint interfaces, the distribution of the elements, and the types of the phases at the welded joints under the assistance of pulsed current were observed, and the reasons affecting the joint strength were analyzed at the microscopic level. The results demonstrate that a welded joint exhibiting a strength of 16.28 MPa can be achieved at 380 °C, combined with conditions of 40 minutes of heat preservation, 15 minutes of pressure holding, and a pulse mode of (10 ms:10 ms). However, under the action of pulsed current, the metal atoms will accelerate the diffusion, while the intermediate liquid phase region will accelerate the diffusion rate of the atoms. This, in turn, produces IMC brittle layers such as Al₅Mg₁₁Zn₄ and Al₁₂Mg₁₇, thus reducing the shear strength of the joint. Consequently, it is necessary to incorporate a suitable intermediate layer that functions as a “barrier” and Zn foil composite intermediate layer, thereby enhancing the weld strength.