Abstract: Cu–Al₂O₃ composite powders were fabricated by gas atomization combined with internal oxidation, using as the raw materials to prepare the Al₂O₃ dispersion-strengthened copper deposits on TC18 alloy substrate by cold spraying. The deposits were subsequently annealed at 600 ℃ and 900 ℃, respectively. Scanning electron microscope, energy dispersive spectrometer, and X-ray diffractometer were adopted to characterize the microstructures of Cu–Al₂O₃ composite powders and cold-sprayed deposits. The effects of annealing treatment on microstructure, electrical conductivity, hardness, and wear resistance of the deposits were investigated. The results show that the Al₂O₃ particles exist in three morphologies in Cu–Al₂O₃ composite powders. The first type presents nearly spherical particles with an average size of 14 nm, uniformly dispersed inside the copper matrix. The second type consists of the rod-shaped and equiaxed particles with an average particle size of 100 nm, distributed near the matrix surface with lower density than internal particles. The third type refers to rod-like and ellipsoidal particles with major axis length exceeding 800 nm, located on the copper matrix surface. Cold spraying enables the deposits to retain the fine microstructure of composite powders. The obtained structure is dominated by copper matrix strengthened by dispersed nano-scale Al₂O₃ particles, supplemented by dispersion strengthening of hundred-nanometer Al₂O₃ particles near powder boundaries. After annealing at 900 ℃, the hardness and electrical conductivity of the Al₂O₃ dispersion-strengthened copper deposits reach HV (153.7±1.9) and (82.3±2.9)%IACS, respectively, delivering the superior comprehensive properties compared with counterparts prepared by the conventional powder metallurgy. The volume wear rate of the 900 ℃-annealed deposits is 5.05×10⁻⁴ mm³·(N·m)⁻¹, which is 25% lower than that of the as-sprayed samples.