The microstructure and properties of DZ125 as-deposited and two-stage aging heat treated samples were analyzed by laser deposition single-layer multi-layer experiments on the casting substrate along the longitudinal direction of DZ125. The results show that the microstructure of the sedimentary repair area is planar crystal, columnar crystal and equiaxed crystal structure from the bottom to the top. The repaired area is mainly MC carbide. The heat affected zone will be decomposed into M23C6 by MC due to the input of heat. Compared with the microstructure, after the two-stage aging heat treatment, a new grain boundary is formed in the repaired area, and some MC carbides are decomposed into M6C and M23C6, and the γ" phase size is slightly increased, about 600-800 nm, and the distribution is uniform; The size of the carbides in the area is slightly reduced, the size of the γ" phase is still increasing, and it is cubic. The tensile strength of the two-stage aging heat treatment specimen at 1000 °C is 516 MPa, and the yield strength is 386 MPa, which is 89.7% of the casting respectively. And 97.7%, the elongation rate is 13.6%, reaching 43.9% of the casting; the average hardness of the repaired sample after heat treatment is 473 HV0.3, which is higher than the average hardness of the as-deposited sample 433 HV0.3, and the heat-treated state and the deposited sample along the repair zone, heat The hardness of the affected zone to the matrix is decreasing.