Abstract: In order to study the relationship between microstructure, properties and temperature field of laser cladding nickel-clad aluminum-Al₂O₃-13%TiO₂ coating, the temperature field of laser cladding process was analyzed by ANSYS Workbench numerical simulation technology for single laser cladding.The laser cladding nickel-clad aluminum-Al₂O₃-13%TiO₂ composite coating on 45 steel surface was prepared by using YLS-2000 fiber laser. The microstructure change of the cladding layer was observed by optical microscope, and the microhardness distribution of the coating was measured by HXD-1000TB Vickers hardness tester. The mechanism of the influence of temperature field on the phase transformation and hardness of the coating was furtherly verified. The results show that during the rapid melting and condensation of laser cladding, a strong temperature gradient is generated between the coating and the substrate, which results in a finer surface structure of the cladding layer. As the distance from the spot increases, the structure gradually coarsens, and the hardness on the cross section of the coating first decreases and then increases and then decreases.