Abstract: The diffusion joining of AZ31b magnesium alloy and 7075 aluminium alloy with Zn as the intermediate layer was achieved by using the assisted pulsed current Transient Liquid Phase (TLP) diffusion joining technology. The investigation focused on the influence of diverse surface treatment methods and processing parameters on the strength of the joints. The underlying reasons for this influence were analysed at the microscopic level by observing the organisation 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. The results demonstrate that a welded joint exhibiting a strength of 16.28 MPa can be achieved at 380°C, 40 minutes of heat preservation, 15 minutes of pressure holding, and a pulse mode of (10 ms:10 ms). However, the accelerated diffusion of metal atoms under the action of pulsed current also accelerates the rate of diffusion of the atoms, which results in the production of I-phases such as Al5 Mg11Zn4, Al12 Mg17, and Al12 Mg17. Al5 Mg11Zn4, Al12 Mg17 and other IMC brittle layers, thus reducing the weld strength of the joint. Consequently, it is imperative to persist in the incorporation of a suitable intermediate layer, which functions as a 'barrier' and Zn foil composite intermediate layer, thereby enhancing the welding strength.