Monolithic silica aerogels were prepared with sol-gel process under ambient drying method.Tetraethylorthosilicate(TEOS), methyltriethoxysilane(MTES) and (3-aminopropyl)triethoxysilane (APTES)were used as co-precursors.Diisocyanatehad been used in this study for strengthening the network of silica aerogels in order to keep the silica aerogels integrity.The process of surface modification is importantin the preparation of silica aerogel via ambient pressure drying.In this study, MTES possesses methyl groups which arehydrophobicand it is favorable for producing monolith silica aerogels, for the hydrophobic property of wet-gels would decrease the effect of capillary force which is the main reason for the crack of silica aerogels during the drying process.And APTES provides amino groups which can react with diisocyanate lead to a conformal coating over the surface of silica aerogels networks.The microstructures of the aerogels were observed scanning electron microscope(SEM).It shows them a well-developed network and strong backbone structure.The TG curve indicates the organic matter takes up considerablepart, it also reveals the diisocyanate reacted with amino groups from APTES.The porosities, densities and specific surface areas of silica aerogelsare in the ranges of 76.3~89.6%, 0.352~0.659 g cm-3, and 91.271~187.206 m2 g-1, respectively.