The synthesis method of Al2 OC by adding B2O3 was studied to modulate the traditional synthesis process. The mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2 h in flowing argon atmosphere to get the Al2 OC product.The results indicate that the addition of B2O3 promotes the formation of Al2 OC,which is dependent on the addition of B2O3,and the Al2 OC content in the products increases with the increase of carbon. By systematically exploring the ratio of active carbon,alumina and boron oxide,the best formulation and the corresponding reaction mechanism were determined. The mixtures of active carbon, alumina and boron oxide with different carbon contents were heated at 1 700 ° C for 2 h in flowing argon atmosphere to get the Al2 OC product. The results indicate that the addition of B2O3 promotes the formation of Al2 OC, which is dependent on the addition of B2O3, and the Al2 OC content in the increase of the increase of carbon. By systematically exploring the ratio of active carbon, alumina and boron oxide, the best formulation and the corresponding reaction mechanism were determined.