This paper describes the technology and optical properties of the selective absorber coating prepared on industrial pure aluminium or aluminium alloys by the anodizing and colouring method. The optical properties of the coating are solar absorptance αs= 0.94 (AM2) and normal thermal emittance ϵ = 0.10; the coating was stable during the ageing test. Scanning electron micrographs of surface morphology and fracture section as well as Auger depth profiling data of the coating are given. Based on this information, a coating structure model of Ni particle pigmented A12O3film is proposed in which the Ni concentration has a graded distribution. Bruggeman effective medium theory and multilayer matrix technique are used to calculate the spectral reflectance of the coating in the wavelength range 0.3 to 20 μm. The result shows that the theoretical value is approximately in agreement with the experimental data. The effect of morphology on the optical properties of coatings is also discussed.