Abstract: To extend the service life of semi-steel rolls, the effects of different Mo contents on the high-temperature friction and wear properties of laser-clad iron-based coatings were analyzed. The surface of worn-out semi-steel rolls was repaired via laser cladding, and the cladding layer used Fe-Cr-Ni-Mo alloy powders. The microstructures of the cladding layers were analyzed using instruments such as an optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscope (SEM), and HBRV-187.5 Brinell-Rockwell-Vickers hardness tester. High-temperature friction and wear tests were conducted on the repaired rolls using a high-temperature friction and wear tester, and the effects of different Mo contents on the high-temperature friction and wear properties of the remanufactured samples were analyzed. The results indicate that the cladding layer primarily consists of ferrite, martensite, and a small amount of retained austenite and contains a small amount of M₇C₃-type and Mo2C carbides, Fe-Cr, and (FeNi) solid solutions, as well as metallic solid solutions formed by Fe and Mo; with the increase of Mo element content, the microstructure distribution of the cladding layer becomes more uniform; the hardness of the cladding layer first increases and then decreases, and the friction coefficient of the cladding layer first decreases and then increases; when the mass fraction of Mo is 4%, the hardness value of the cladding layer is the highest (55.3 HRC), which is increased by 28.6% compared with that of the substrate; the friction coefficient is the lowest (0.29), which is decreased by 10.1% compared with that of the substrate; the friction and wear type transforms from the adhesive wear and delamination wear of the substrate into abrasive wear. In summary, the repaired remanufactured samples effectively extend the service life of semi-steel rolls.