The preparation of ZrB2/SiC anti-oxidation ablation coating on the surface of C/C composites can effectively improve the oxidation ablation in high temperature oxidation environment. However, the problem of low thermal conductivity and low high-temperature emissivity of ZrB2/SiC coating oxidation products began to become prominent, and the coating heats up too quickly during the service. In this paper, a new idea of combining oxidative ablation and radiation is proposed. The surface of ZrB2/SiC particles is modified by high-emitting rare earth oxide materials to improve the thermal radiation capability of the coating and maintain the coating temperature within a suitable range. In this paper, Sm2O3 modified ZrB2/SiC coating was designed, ZrB2/SiC/Sm2O3 composite powder was synthesized and IPS was used to induce plasma spheroidizing sintering (IPS). The coating was prepared by atmospheric plasma spraying (APS). The existence and distribution characteristics of Sm2O3 in powder and coating were investigated. The influence mechanism of Sm2O3 on powder and coating characteristics was analyzed. The evolution of powder and coating characteristics was studied. The oxy-acetylene combustion flow was used. OAF evaluated the oxidation ablation performance of the coating and evaluated the effect of infrared emissivity after the introduction of Sm2O3.