Abstract: In the present work，micro/mesoporous silica modified with methyl groups was prepared via the non-surfactant method using tetraethylorthosilicate (TEOS) and polymethylhydrosiloxane (PMHS) as silica sources，and their structural properties were characterized with N2 adsorption/desorption，High Resolution Transmission Electron Microscopy (HRTEM) and thermogravimetric analysis (TG). The results showed that the prepared products were micro/mesoporous materials with high hydrophobility and thermal stability. Three micro/mesoporous materials with different micropore/mesopore ratios were prepared by adjusting the mass ratio of PMHS/TEOS，and the separation performance of benzene and its derivatives on the three materials were further studied by using the pulse chromatography technique. Benzene and its derivatives can be fully separated on the micro/mesoporous materials，and the retention time increased with the increase of the mass ratio of PMHS/TEOS. Henry constant，adsorption heat，separation factors followed the same order：n-butylbenzene＞n-propylbenzene＞ethylbenzene＞toluene＞benzene. Henry constant，adsorption heat，separation factors increased with the increase of the mass ratio of PMHS/TEOS.