Using Ni₃Al+Cr₃C₂ mixed powder with different amounts of Cr₃C₂, laser cladding was carried out on 45 steel to prepare Ni₃Al-based alloy cladding layer. By means of scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and wear tests, the content and average size of in situ-formed carbides under different amounts of Cr₃C₂ were calculated, and the effects of carbides on the microstructure, microhardness and wear resistance of Ni₃Al-based alloy cladding layer were analyzed. The results indicate that the microstructure of the Ni₃Al-based alloy cladding layer contains mainly Ni₃Al matrix and in situ-formed Cr₇C₃ carbides. With the increase of Cr₃C₂ content, the proportion of in situ-formed carbides in cladding layer increases from 6.8% to 32.3%, the average size increases from 0.10μm to 0.78μm, and the microhardness of the cladding layer increases from 471HV to 609HV. When the content of Cr₃C₂ is 35%, the carbide particles are dispersed, and uniform wear is produced in the process of wear test, so that the wear less of cladding layer is as low as 0.19 mg, and the wear loss of the disk is relatively the lowest, about 1.23 mg. However, when the content of Cr₃C₂ is 45%, the carbide content is 32.3%, but the large size particles are mainly. In the process of wear test, the large particles of carbide fracture and spalling, which accelerates the wear of the disk.