The work aims to improve the absorptance of Co-WC solar selective absorbing coating. Sol-gel method was used to deposit the Co3O4-CoAl2O4 solar selective absorbing film on the WC-Co coating prepared with high-velocity oxy-fuel (HVOF) spraying. The samples were annealed at different atmospheric temperature. The components of coatings annealed at different temperature were analyzed by X-ray diffraction (XRD). The microstructure and the surface roughness of the coatings were investigated by field emission scanning electron microscopy (FE-SEM) and surface roughness meter. The performance of Co3O4-CoAl2O4 coatings was studied by calculating the mass change of the coatings with balance. The element distribution of the Co3O4-CoAl2O4 coatings was analyzed by energy dispersive spectral (EDS). The absorptance of coatings was studied by UV-Vis-NIR spectrophotometer. The absorption properties of Co-WC coatings was improved by dipping the Co3O4-CoAl2O4 films. Co3O4-CoAl2O4 coating annealed at 650 ℃ obtained the excellent absorption with α=0.901. The surface was typical spinel structure with fine grain size and surface roughness of 3.519 μm. The mass change of Co3O4-CoAl2O4 coatings annealed at 650 ℃ was the minimum compared with coatings under other annealing temperatures. The mass change of the coatings was 14.9 mg in the experiment of anti-ultrasonic spalling for 40 h and 0.5 mg in the thermal shock resistance for 20 times. At the same time, the absorptance maintained at about 0.89. Co3O4-CoAl2O4 film can improve the surface state of Co-WC coating and increases the absorption performance through selecting suitable annealing temperature.