•High quality FeCrMoMn coatings were fabricated by high-speed laser cladding.•Mechanism of laser acting on powders during high-speed laser cladding.•Metallurgical behavior of solute trapping during rapid solidification of laser molten pool.•Evolution mechanism of corrosion resistance of high-speed laser clad coatings. In this research, FeCrMoMn coatings with excellent corrosion resistance and metallurgical quality were deposited on the 45# steel substrate by conventional and high-speed laser cladding at the scanning speed of 0.4 m/min, 40 m/min and 70 m/min, respectively. Their microstructure, phase composition, hardness and corrosion resistance were characterized and compared. The results show that compared with the conventional cladding, high-speed laser cladding leads to a decrease in grain size, heat affected zone, and the dilution rate of the coatings due to solute trapping of coatings. Metallurgical bonding is formed between the substrate and the coatings, and the hardness and electrochemical corrosion resistance of the coatings are also significantly improved.