Abstract: The mechanism and performance of the thermal insulation of nano-sized SiO₂ composite insulation materials were described.The research status on the nano-sized SiO₂ composite insulation materials made by the sol-gel process and vapor phase method was summarized. Some problems that existed during the preparation process of the nano-sized SiO₂ composite insulation materials with the two methods were analyzed respectively.Some functional additives including the infrared opacifiers，reinforced materials，and high temperature contraction inhibitors were introduced in detail.These materials have a significant influence on the properties of the nano-sized SiO₂ composite insulation materials.The development trend of nano-sized SiO₂ composite insulation materials was prospected at last.

Key words: nano-sized SiO₂, composite insulation materials, functional additives