Abstract: The silica aerogel has the characteristics of high porosity and low thermal conductivity，which make it a new super thermal insulation material.However，because of its poor flexibility and integrity，and the rapidly increase of thermal conduc- tivity at high temperature when the aerogel is prepared through ambient pressure drying，the applications of silica aerogel are limited. Recently，silica aerogel composites with enhanced flexibility，integrity，and high temperature heat insulation property were prepared by in-situ sol-gel process and molding method.This make it is possible to using those silica aerogel composites as thermal insulating materials.The thermal insulation principles and properties of silica aerogel were illustrated，the research progresses of high temperature radioprotective type silica aerogel composites，fiber-reinforced silica aerogel composites，and polymer-reinforced silica aerogel composites in recent years were reviewed.At last，the future prospect of the silica aerogel composites was also discussed.

Key words: silica, aerogel, composite thermal insulation materials