The work aims to explore application of SiO2 aerogel in composite thermal insulation coating, and achieve heat insulation by reducing thermal conductivity of composite heat insulation coating, improving reflectivity and emissivity based on mechanism of thermal insulation. First of all, content of each filler was determined by performing single-doped experiment, and ultraviolet/visible/near infrared spectrophotometer, infrared emissivity measuring instrument and homemade testing insulation device were used to analyze emissivity, radiation rate and heat insulation performance of the coating. Finally, optimal formula of thermal insulation coating was obtained in orthogonal experiment method. SiO2 aerogel could reduce thermal conductivity of the coating, on this basis, adding pigments such as titanium dioxide, hollow glass microspheres and far-infrared ceramic powder could improve the reflectivity and radiance of the coating, and further enhance the effect of heat insulation. The composite thermal insulation coating exhibited best thermal insulation performance when 5% (mass fraction) of SiO2 aerogel, 5% of titanium dioxide, 5% of the hollow glass microspheres and 10% of far-infrared ceramic powder were added. Compared to that of uncoated blank sample, the temperature could be reduced by up to 14.8 ℃ when dry film thickness of SiO2 aerogel composite heat insulation coating was 60 μm. SiO2 aerogel composite thermal insulation coating has excellent thermal insulation performance, and features in thinness, light weight and environmental protection, and is of certain value of practical application.