The　mechanical　properties　of　SiO2　aerogel　prepared　under　atmospheric　pressure　are　poor,　so　it　is　difficult　to　prepare　large　pieces　of　materials　for　practical　engineering.　In　this　paper,　trimethylchlorosilane　(TMCS)　was　used　as　a　surface　modifier　to　transform　hydrophilic　substances　with　higher　surface　activity　into　hydrophobic　groups,　to　improve　the　network　strength　of　SiO2　aerogel.　Super-hydrophobic　SiO2　aerogel　was　prepared　by　the　sol-gel　method　under　atmospheric　pressure.　The　effects　of　trimethylchlorosilane　on　the　structure　and　properties　of　SiO2　aerogel　were　characterized　by　a　specific　surface　area　analyzer,　Fourier　transform　infrared　spectrometer,　thermal　conductivity　meter,　static　contact　angle　meter,　and　scanning　electron　microscope.　The　results　show　that　the　SiO2　aerogel　prepared　when　n　(Si):n　(TMCS)　is　1　has　the　best　performance.　Its　density　is　as　low　as　0.0759　g/cm3,　the　porosity　is　as　high　as　96.5%,　the　specific　surface　area　is　as　high　as　723.08　m2/g,　and　the　contact　angle　is　163.8°.　It　has　good　hydrophobic　properties.　©　Published　under　licence　by　IOP　Publishing　Ltd.