The composite specimens have been prepared using fused corundum, silicon and bauxite-based β-SiAlON powder as starting materials. The physical properties, high temperature modulus of rupture (HMOR), thermal shock resistance (TSR), phase composition and microstructure of the specimens after firing at 1500°C have been studied. The results show: (1) Al2O3-SiC-SiAlON composites are sintered well at 1500°C. (2) HMOR and TSR of the specimens increase with increase of Si content, high temperature properties are further increased with appropriate β-SiAlON addition. (3) The in-situ formed SiC and O’-SiAlON fill in the interstices of corundum skeleton structure, forming interlocking network structure, thus creating strengthening and toughening effects.