<p>Laser cladding technology is broadly utilized owing to its outstanding surface modification capability. However, during the cladding process involving the tungsten carbide hard phase, defects such as inclusions, pores, and cracks tend to occur, significantly compromising the service performance of the components. Applying an alternating magnetic field can generate an electromagnetic stirring effect within the weld pool, optimizing the thermal and mass transfer process, and refining the grain structure. In this paper, a numerical model integrating multiple fields for the laser cladding process of 42CrMo alloy with nickel-based WC60 composite powder was build. The transient evolution characteristics of multiple fields during the cladding processes without and with magnetic field were obtained. The instantaneous height data of the coating layer were extracted. Research indicates that the application of an alternating magnetic field enhances the flow rate of the weld pool, reduces temperature gradients and thermal stress, and influences cladding height. The morphology, composition of phases, and roughness of the coating layer were obtained through scanning electron microscope, x-ray diffraction, and roughness observation. The findings indicate that the magnetic field has a substantial impact on the coating profile and surface roughness. As the field strength increases, the roughness decreases. This study establishes a critical theoretical foundation for refining cladding process parameters and enhancing coating quality.</p>