In order to improve the performance of silica aerogels,trimethylchlorosilane(TMCS)was selected as the secondary modifier on the basis of the one-step preparation of silica aerogel powder by one-step method,and the effect of the properties of the silica aerogels synthesized by secondary modification was studied.The results showed that the secondary modification of silica aerogels on the basis of one-step method further improved the properties of silica aerogels.Compared with the one-step method,the second-modified SiO2 aerogel gel is more hydrophobic,with a hydrophobic angle of 163.5°,superhydrophobic performance,and the optimal density is as low as 0.117g/cm3.