We have synthesized monolithic diatomite/silica aerogels by incorporating dispersion modificated diatomite during the sol-gel polycondensation of the tetraethoxysilane precursors.The influences of the diatomite content on the microstructural properties were studied by scanning electron microscopy and transmission electron microscopy.The specific surface area and pore structure were analyzed via specific surface and pore size analysis instrument.The thermal insulation properties of composite aerogels were researched by thermal conductivity measuring instruments.In the samples investigated, the diatomite were uniformly dispersed in the silica aerogel, which resulted in the unique formation mechanism of silica network with the diatomite as template that could affect the thermal conductivity of aerogels varying form 0.035 W/m K to 0.058 W/m K.The diatomite/silica aerogels with outstanding properties prepared by sol-gel polycondensation method are potential for building insulation applications.