Expanded vermiculite is an important thermal insulation material with a layered micro-porous structure. In this paper, modified expanded vermiculite was obtained using an in-situ gel method. Under experimental conditions of n (epoxy propane) :n (A1(NO3)3) : n (ethanol) =5.5:1:30, the alumina aerogel was distributed evenly in the structural gaps of the expanded vermiculite. The framework of the in-situ alumina aerogel is composed of sphere-like Al 2 O 3 particles with a diameter of 40nm and the pore size distribution is uniform with an average size of 45nm. The modified vermiculite maintains a good multi-porous network structure, without any distinct signs of conglobation or collapse of the porous structure after being calcined at 900°C and 1000°C for 4h. The modified expanded vermiculite show lower thermal conduction than the non-modified expanded vermiculites at all temperatures tested.