The purpose of this study was to investigate the oxidation of ZrB2/ZrO2 (ZZ) and ZrB2/ZrO2/SiC (ZZS) ceramics. The ceramics were fabricated by spark plasma sintering (SPS) at 1900°C and exposed to ten-minute oxidation cycles in stagnant air at 1200°C in a box furnace with molybdenum disilicide heating elements. Results of relative density, surface phase change and the rate of weight growth show that the addition of ZrO2 improved the sintering properties of ZrB2 ceramics. While the resistance to oxidation declined with the increase content of ZrO2. And the addition of SiC improved the resistance to oxidation of ZrB2/ZrO2 composites significantly.