Calcium cobaltate thin films were prepared by coating and sintering on alumina ceramic substrate with calcium cobaltate powder prepared by sol-gel method. The phase structure， temperature resistance characteristics and wave-absorbing properties of the thin films were studied. It is found that the calcium cobaltate powders prepared by sol-gel method are composed of Ca9Co12O28 phase, and the powder particles are uniform, with a certain orientation growth and obvious lamellar structure. The sintered calcium cobaltate film is composed of fine Ca3Co4O9 phase, which is closely bound to the alumina substrate. The thickness is about 20 μm. The square resistance of the films decreases rapidly with the increase of temperature, and keep around 20 Ω/□ at 300 ℃ to 800 ℃. At 800 ℃, the resistance-film type metamaterial absorber exhibits double absorption peaks at 8 GHz to 18 GHz.