Using TMOS as silica sources, silica aero-gels were synthesized via microwave assist Sol-Gel method and were synthesized into hydrophobic silica aero-gels by the surface chemical modification of TMCS followed by ambient pressure drying technique. The structure, surface morphology, and chemical composition of the produced samples in the experiments were characterized by test methods, such as FTIR, SEM, XRD, BET and TG-DSC. The results showed that the produced samples are hydrophobic silica aero-gels with homogeneous distribution. The specific surface areas of the synthesized silica aero-gels via microwave assist Sol-Gel method is 1096m2?g-1, whose pore diameters mainly range from 2 to10 nm. The contact angle with water is 141?, which shows the super hydrophobic. The resistance temperature of the silica aero-gels are 543℃.The silica aero-gels has good thermal stability.