The oxidation behavior of SiBCN ceramics, derived from pyrolysis of polymeric precursor, was inves鄄 tigated by oxidizing the SiBCN ceramics at 1 200益under air for different time. As a reference, SiCN ceramic was studied using the same process. The results show that after oxidation for 10 h, the weight gain of SiBCN is only 0郾35% and the ceramic keeps its original morphology without cracks. Whereas, the oxidation of SiCN results in a weight gain of 3. 10% and cracks. The elemental composition of the sample surface is mainly SiO2 for SiBCN and SiOx (x<2) for SiCN ceramics, respectively