To enhance the thermal insulation properties of coatings，double-layer coatings were constructed. The coatings were prepared with silica sol and styrene-acrylic emulsion as the main and auxiliary film-forming compounds，respectively. The bottom and top coating contained SiO₂ aerogel and flaky aluminum powder as their thermal insulation fillers，respectively. The behavior of flake aluminum powder and SiO₂ aerogel thermal insulating fillers on the thermal insulating properties of double-layer coating was systematically investigated，and the related thermal insulating mechanisms were discussed. The results indicated that the optimal insulation effect was achieved with 4% aluminum powder addition，resulting in the insulation temperature difference of 9. 1 ℃ compared with that ofthe blank board sample. For the SiO₂ aerogel-based coating，the optimal addition for bestthermal insulation was 4%-5%. The addition of flaky aluminum powder could render it withthe reflection-type thermal insulation property，while the addition of SiO₂ aerogel could render it with the barrier-type thermal insulation property. By combining the thermal insulation characteristics of both，a double-layer coating structure with dual mechanism thermal insulation properties was successfully constructed，with a thermal insulation temperature difference of 10. 9 ℃，which was higher than the thermal insulation effect of a single coating.