To improve the wear resistance of brake disks, the Ni60A coating was prepared on 20CrNiMo steel using laser cladding by optical fiber-based laser system. The microstructure, composition uniformity, hardness, dry-sliding wear performance, and friction and wear mechanism of the Ni-based alloy coating were investigated. The results show that the coating consists of γ-Ni, M₂₃C₆, Ni-Cr-Fe, Ni₃B, [Fe, Ni], FeNi₃, NiC, FeNi, and other phases. The average microhardness HV_0.3 of Ni-based alloy coating is 4600 MPa, which is 2.63 times higher than that of the 20CrNiMo steel substrate. Compared with the substrate, the coating exhibits lower average friction coefficients under working condition of high load and high temperature, and the wear resistance significantly improves. When the load is 150 N, the wear resistance of the coating increases by 15.3 and 22.0 times at room temperature and 400 °C, respectively. With the increase of temperature and load, the wear mechanism of the coating changes from abrasive and adhesive wear to oxidative and abrasive wear.