Ultra-light calcium silicate material constructed with fibrous xonotlite crystals has an advantage of low-thermal conduction coefficient. But the microporous structure can hardly make a better performance in terms of super thermal insulation. Although nanoporous structure of SiO2-aerogel satisfies the requirement, its tenacity is not strong enough to produce by itself blocky super thermal insulation material. This research, thus proposes to apply SiO2-aerogel as nanoporous carrier in the process of preparation, with Ultra-light calcium silicate material constructed with fibrous xonotlite crystals as the matrix so as to prepare nanoporous super thermal insulation material compounded with Xonotlite-SiO2-aerogel via so-gel method and ethanol supercritical drying. SEM and pore size distribution techniques were here applied to characterize the morphology and pore structure of the composite material. The results show that the SiO2-aerogels were better distributed in pore of calcium silicate matrix, with the pore size distribution of composite ranging from 10 nanometers to 50 nanometers, and average pore size less then 20 nm.