To improve the oxidation resistance property of C/SiCO nanoporous ceramic composites, TaSi2-MoSi2-borosilicate glasscoatings and TaSi2-MoSi2-ZrB2-Borosilicate glass coatings were prepared on the surface of C/SiCO nanoporous ceramiccomposites through slurry brushing combined with graphite powder embedding sintering process. The coatings are smooth,flat, without cracks, and tightly bonded to the substrate material. A study was conducted on the thermal stability of coatedsamples in an air atmosphere at 1600 ℃ and the high-temperature oxidation mechanism was analyzed. The results show thatthe coating effectively improves the thermal stability of SiCO nanoporous ceramic composites, and the addition of ZrB2 furtherimproves the oxidation resistance and ablation resistance of the coated samples. At high temperatures, the borosilicate glassin the coating displays a viscous flow state, and the SiO2 glass layer formed on the coatings surface serves as an oxygen barrier. At the same time, the coating has a particle reinforced glass structure inside, which avoid the growth and propagation of cracksand reduce oxygen diffusion channels effectively.