Low-carbon Al2O3-C refractory samples were prepared from raw materials of tabular alumina, reactive alumina powder, flake graphite and carbon black. Silicon powder and metallic Al powder were used as additives and phenol resin was used as binder. The effects of nitrogen partial pressure and firing temperature on microstructural evolution and the thermo-mechanical properties of low-carbon Al2O3-C refractories were investigated. The thermodynamic calculations for Al–Si–O–C–N systems suggested that SiC, AlN and β-Sialon could be stable under different nitrogen partial pressures. The experimental results showed that short columnar AlN and SiC whiskers were formed at 1200°C. The aspect ratio of AlN was higher and SiC production become larger with nitrogen partial pressure increasing. Two-dimensional flaky β-Sialon could be generated as the nitrogen partial pressure increased to higher than 0.11MPa at 1400°C. Due to the formation of SiC whiskers and β-Sialon, the cold modulus of rupture and the cold crushing strength were improved from 12.8MPa to 19.3MPa and from 57.3MPa to 74.7MPa, respectively. The load displacement could be increased by 62% to 0.59mm. At the same time, the maximum values of flexural modulus and hot modulus of rupture reached 4.2GPa and 13.2MPa, respectively. After three thermal shock cycles, the CCS of refractories containing the SiC whiskers and β-Sialon only decreased by 6.2MPa. The in situ formation of SiC whiskers and β-Sialon could greatly enhance the thermo-mechanical properties of low-carbon Al2O3-C refractories.