To seek an effective strategy for improving the compatibility of carboxyl methyl cellulose (CMC) with silica fume-based geopolymer composite flameretarding coatings, a novel silica aerogel (SA) doped inorganic siliceous hybrid coating is fabricated by sol-gel. Results show that an appropriate dosage (0.5 wt%) of SA ameliorates their compatibility thus imparting an enhanced flame resistance, evidenced by the lowest value of fire growth index (0.22 kWÁm À2 Ás À1 ) decreased by 55% and the average effective heat of combustion (4.16 kWÁkg À1 ) decreased by 31%, the raised flame retardancy index of 5.54 from 1 compared with the control. Because the SA improves the compatibility between the CMC and siliceous colloidal sol, due to its high reactivity, electrostatic repulsion involved in SiO(OH) 3 À , and high porosity, leading to an enhanced crosslinking during film-forming of the hybrid coatings. Meanwhile, the reduction between CMC and silica occurs with a swelling fire shield, evidenced by the generated silicon involved in the as-formed amorphous siliceous residues. Therefore, it proposed a new strategy for optimizing the compatibility of organic-inorganic hybrid fireproof coatings, revealing an efficient design of CMC/inorganic siliceous flame retardants, high-value recycling technology of solid waste, low-carbon, and sustainable materials.