Abstract: The hydrophobic polyimide (PI) reinforced silica aerogel composite was prepared by the methods of chemical cross-linking, sol-gel and surface modification. The 3-aminopropyltriethoxysilane (APTES) end capped polyimide synthesized from pyromelliticdianhydride (PMDA), 4,4'-oxydianiline (ODA) as the polymer monomers and APTES as the blocking agent, was mixed with tetraethoxysilane (TEOS) to form the precursor. The PI reinforced SiO₂ aerogel composite samples were obtained via a technological process of acid/base two-step catalytic, surface hydrophobic modification, solvent exchange and carbon dioxide supercritical fluid drying. The chemical composition, micro-morphology, porous structure, mechanical and hydrophobic properties were studied by the FTIR, SEM, specific surface analyzer, universal testing machine and contact angle analyzer. The results show that the density of PI reinforced SiO₂ aerogel composite with 6wt% PI mass fraction is 0.124 g/cm³, the specific surface area is 724 m²/g, the average pore size is 14 nm, the water contact angle is 134° and the compressive strength is 0.295 MPa. When the PI mass fraction is up to 20wt%, the compressive strength of the sample is 0.556 MPa.