Effects of different silicon carbide contents on thermal shock resistance properties of mullite-bauxite castable refractory were analyzed respectively by taking the mullite, bauxite as main raw materials and taking calcium aluminate cement as a binding system. After 24 h curing in mould and another 24 h curing at 110° after demoulding, the samples were heated at 1000, 1300 and 1500° for 3 h in air, respectively. The bulk density, thermal expansion coefficient and thermal shock resistance were examined. The results showed that there was a great effect of content of SiC on bulk density, thermal expansion coefficient and thermal shock resistance of mullite-bauxite castable. Under the experimental conditions, the castable performed the best thermal shock resistance when w(SiC)=5%–10%.