IN625 superalloy was used to repair the surface of EA4T axle steel by laser. The phase composition, microstructure, grain size and mechanical properties of different areas of IN625 laser cladding samples were analyzed by X-ray diffractometer, scanning electron microscope, Vickers hardness tester and universal experimental machine. The results show that the bottom of the IN625 laser cladding layer is the columnar crystal structure with multiple growth directions, the middle is the columnar crystal structure with single growth direction and the grain size is the largest, and the top is the mixed crystal region dominated by equiaxial crystal; The interdiffusion of Ni, Cr and Fe occurs between the cladding layer and the substrate, and the diffusion region is about 9 μm. The microhardness is 295HV_0.2, the tensile strength is 888 MPa and the elongation is 38.0% .