A laser deposition repair experiments were carried out on DZ125 casting substrate. The microstructure, hardness and friction and wear properties of laser deposition were studied. The results show that the morphology of the deposition area from bottom to top is as follows:Planar crystals with a width of about 8μm and columnar crystals with close arrangement along the deposition direction are grown. The dendrites in the middle of the sedimentary zone and the chaotic equiaxed crystals at the top. The size of γ "phase at the boundary of the deposit zone is larger than that of the layer, and the size of the γ" phase at the grain boundary is larger than that of the crystal, the phenomenon of the distribution of the eutectic and the mc carbides along the grain boundary is obvious, Different morphologies of MC carbides were found in the deposited area.Most of the MC carbides in the middle and lower parts of the deposit area are short rod-like MC carbides, and the top of the deposit areas are mostly small blocks and octahedral MC carbides.The microhardness of the deposited area is about 455～475 HV0.3, which is higher than that of the substrate 410～420HV0.3.The wear resistance of the deposition area is superior to that of the matrix, and the wear mechanism is mainly abrasive wear .