<p>Alternating magnetic field-assisted laser cladding technology can effectively improve the quality of the cladding layer, but the underlying multi-physics field coupling mechanism is still unclear. This study aims to quantitatively reveal the key electromagnetic effects, distribution, and evolution laws within the workpiece during laser cladding through numerical simulation methods. Based on the Maxwell equations, a three-dimensional transient numerical model of the alternating magnetic field experimental platform was established, and the dynamic distribution characteristics of the spatial magnetic field were analyzed. The focus was on the eddy current effect induced by Faraday's law of electromagnetic induction in the magnetic workpiece, the subsequent Joule heating effect (magnetic heat effect), and the dynamic behavior of the Lorentz force. The research results show that the spatial magnetic field intensity changes periodically with the excitation current, and the maximum magnetic induction intensity at the center of the workpiece can reach 90.4 mT. The highest induced eddy current density is 8.45&#xa0;×&#xa0;10⁵&#xa0;A/m², and its distribution strictly follows the skin effect, concentrating on the surface of the workpiece. The peak power density of the volumetric heat source generated by eddy current dissipation reaches 4.3&#xa0;×&#xa0;10⁴&#xa0;W/m³, achieving an internal-to-external preheating effect. The Lorentz force density has four peaks within a cycle (the highest is 4.3&#xa0;×&#xa0;10⁴&#xa0;N/m³), and its direction changes every quarter cycle, forming a periodic electromagnetic stirring effect on the molten pool. This study elucidates the intrinsic mechanism by which an alternating magnetic field regulates heat distribution and melt flow, thereby affecting the solidification process. It provides an important theoretical basis for optimizing laser cladding and repair processes of magnetic materials.</p>