The work aims to improve the radiation property of Cr2O3- TiO2-based ceramic coating. Cr2O3, TiO2, NiO and Tb4O7 were used as raw materials to prepare Cr2O3-TiO2-based composite powders with mix structures of spinel and perovskite by spray drying and high temperature sintering densification treatment. Tb4O7 doped Cr2O3-TiO2-based high emissivity coatings were prepared on TC4 titanium alloy surface by atmospheric plasma spraying. The microstructure, phase composition and radiation property of samples were respectively characterized by SEM, XRD, and IRE-2 infrared radiometer. The sphericity and fluidity of the composite powders were preferable after agglomeration and suitable for continuous plasma spray. The prepared Cr2O3-TiO2-based ceramic coatings were in good melting state and high flatting degree and the distribution of Tb elements doped in the coatings was uniform. The doped rare earth elements like Tb4+ and Tb3+ ions replaced Ni2+ and Cr3+ with similar radius in the NiCr2O4 spinel. Thus, the uniformity of the single crystal structure was damaged, and the change of the cell volume inevitably caused the lattice distortion, then the radiation belt was strengthened and widened obviously. The emissivity of coatings went up as the content of Tb4O7 increased, and the normal total emissivity ran up to 0.91 at 600 ℃ when the dopant amount of Tb4O7 reached 7.5wt.%. The addition of rare earth oxide like Tb4O7 can effectively improve the emissivity of Cr2O3-TiO2-based ceramic coating, and the doped rare earth can cause crystal structure distortion of spinel, so as to improve the radiation property of coating.