Electromagnetic stirring technique is introduced into the processing of laser cladding for preparing Co-based alloy coatings. In this research, a detailed analysis of hot corrosion resistance is conducted for a cladding layer applied in a salt mixture at 750 ℃ for 100 h with and without the assistance of electromagnetic stirring. The cladding layer is found to have poor hot corrosion resistance without magnetic field assistance. After hot corrosion for 60 h, the inside of the coating shows severe internal oxidation and vulcanization as well as substantial weight loss. In contrast, electromagnetic stirring produces a cladding layer that effectively suppresses the inward intrusion of S and Cl - ions in the etching solution. This suppression facilitates the formation of stable protective Cr2O3 and CoCr2O4 spinel oxide films so that only slight cracking and peeling occur during the entire hot corrosion stage. The addition of electromagnetic stirring effectively refines and homogenizes the microstructure of the coating, and also promotes the rapid formation of a protective oxide film on the coating surface, which can prevent the diffusion of molten salt; thus, the hot corrosion resistance of the coating can be further improved.