To further improve the high-temperature service performance of DZ125 alloy, the rare earth element Y-modified Cr-Al co-deposition coating was prepared via the pack cementation method on the DZ125 alloy surface. The effects of Y₂O₃ content on the oxidation resistance at high temperature and the microstructure and phases of the co-deposition coating were studied. Results show that the Cr-Al-Y coatings prepared under different conditions have a triple-layered structure, which is arranged from the outside to the inside as follows: the Cr+Ni₃Cr₂ outer layer, the Ni₃Cr₂+Al₁₃Co₄ middle layer, and the Ni₃Al inner layer. Both the coating thickness and the density are strongly increased with the addition of 0wt%?2wt% Y₂O₃, and they are decreased when the content of Y₂O₃ is further increased to 5wt%. The results of oxidation tests at 1100 °C demonstrate that the Cr-Al-Y coating significantly improves the oxidation resistance of DZ125 alloy at high temperatures.