Abstract: Based on the freeze-drying process and chemical vapor deposition technology, polyvinyl alcohol(PVA) was compounded with cellulose to enhance the mechanical compressibility and dimensional stability of cellulose(CE) aerogels, followed by the fabrication of highly elastic, hydrophobic, and porous CE/PVA composite aerogels. The effects of PVA content on the mechanical properties of CE/PVA composite aerogels were studied. As the mass fraction of PVA increased, the compressive strength of cellulose aerogels increased. When the amount of PVA was 15% of the mass of cellulose, the compressive strain increased to 66 kPa, which was increased by 6.5 times. Simultaneously, the influences of silane modification on the microstructure, thermal stability, hydrophobicity, specific surface area and physical properties of composite aerogels were explored, and the results showed that S-CE/PVA composite aerogel modified by methyltriethoxysilane(MTES) had a denser lamellar structure, the initial decomposition temperature rose to 314.6℃, the water contact angle was as high as 115°, the specific surface area was 109.42 cm³/g, the density was 0.045 g/cm³, and the porosity was greater than 95%.