Laser cladding technology was used to prepare the SDNi45 coating to improve the surface properties of Q235 steel and increase the service life of the fracturing pump plunger. The microstructure of the coating was analyzed in detail by employing X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The hardness distribution of the cross-section of the coating was tested using a microhardness tester. The tribological properties were investigated using a comprehensive surface performance tester. The results show that the phase composition of the coating mainly consists of γ-Ni, WC, W₂C, Cr₂₃C₆, Cr₇C₃, Fe₂B, and Fe₃W₃C. The bottom part of the coating is primarily columnar crystals, and there are also WC particles that are not completely dissolved after sinking. The middle and upper parts are mainly agglomerated reticulated fine grain, and there are also many secondary generated irregular carbides. The average microhardness of the coating reaches 496.5 HV_0.2, which is about 2.5 times higher than that of the substrate, due to fine-grain and second-phase strengthening effects. The friction coefficient of the coating is approximately 0.67 and the wear mechanism is mainly abrasive and adhesive wear.