Silica aerogel is a new type of porous functional material composed of SiO2 particles polymerized with each other,using water/ethanol/n-hexane surfactant-free microemulsion system as solvent,using acid-base two-step sol-gel method to prepare dimethyl-enhanced silicon aerogel without solvent replacement and surface modification.The obtained samples were characterized by SEM,FT-IR,BET and contact angle to determine the optimal dosage of dimethyldiethoxysilane in the enhanced phase.The results showed that when the addition of dimethyldiethoxysilane was 0.08 mol,the density of the dimethyl-enhanced silicon aerogel without surfactant microemulsion was 0.157 g/cm3,the porosity was 93%,the average pore size of BJH was 3.92 nm,and the hydrophobic angle was 152.5°.