Abstract: A high-aluminum bronze coating was prepared on 45 steel substrate by highly efficient supersonic plasma spraying technology. The coating layers with different Ce content were investigated by XRD, SEM, EDS, EPMA, OM and Microhardness tester. The results show that the coating became denser,and hard K phase dispersively distributed with the increase of Cerium content. Ce played a crucial role in transition procedure of AlFe₃ and Al₁₃Fe₄ into AlFe, AlFe₃ and AlFe₃ in K phase, and the composition of K phase was Al₁₃Fe₄ when Ce content was more than 0.4%. Al segregated with the addition of Ce, and Ce contributed to transition of Al from big flake particle to platelet particle. The hardness of coating first decreased and then increased with the increment of Ce. When Ce content was more than 0.4%,the hardness and stability of coating was better than that without Ce.