Abstract: The effects of different silica micropowders addition on the volume density, thermal expansion coefficient and thermal shock resistance properties of flint clay based spraying refractory were studied by taking flint clay, aluminate cement and so on as main raw material. Mold unloading after natural drying for 24 h and drying at 110 ℃ for 24 h, the specimens were calcined at different temperatures for 3 h, respectively. The microstructure was observed by SEM. The results show that volume density of flint clay based spraying refractory increased and thermal expansion coefficient decreased with the increase of silica micropowders addition. The flint clay based spraying refractory performed the best thermal shock resistancewhen the content of silica micropowders was 5wt%.