Fe901/Al2O3 metal matrix composite (MMC) coatings were deposited on the surface of 45 steel via electromagnetic field (EF)-assisted laser cladding technology. The influences of EF on the microstructure, phase composition, microhardness, and wear resistance of the Fe901/Al2O3 MMC coating were investigated. The generated Lorentz force (FL) and Joule heating due to the application of EF had a positive effect on wear resistance. The results showed that FL broke up the columnar dendrites. Joule heating produced more nuclei, resulting in the formation of fine columnar dendrites, equiaxed dendrites, and cells. The EF affected the content of hard phase in the coatings while it did not change the phase composition of the coating, because the coatings with and without EF assistance contained (Fe, Cr), (Fe, Cr)7C3, Fe3Al, and (Al, Fe)4Cr phases. The microhardness under 20 mT increased by 84.5 HV0.2 compared to the coating without EF due to the refinement of grains and the increased content of hard phase. Additionally, the main wear mechanism switched from adhesive wear to abrasive wear.