Abstract: Sialon-bonded corundum castables were prepared by in-situ nitridation sintering with tabular alumina as the aggregate,fused white corundum fine,hydratable alumina,Si powder and ultra-fine alumina as the matrix.The effects of sialon content on their physical properties,high-temperature strength and thermal shock resistance were investigated.The phase composition and microstructure of the samples were characterized by XRD and SEM.The results show that with increasing sialon content the water demand of the castables increases,the cold modulus of rupture and bulk density decrease,the apparent porosity slightly increases,and the permanent linear change varies from little shrinkage to little expansion.The hot modulus of rupture and thermal shock resistance of the castables obviously improve with increasing sialon content,and the residual strength ratio increases from 16% without sialon to 50%.