In this work, oxidation of silicon carbide particles (SiCp) at elevated temperature and its influence on the interface layer and thermal conductivity of SiCp/ZL101 composites prepared using pressure infiltration process were investigated respectively. It is found that initial temperature for the oxidation of SiCp is about 850 degrees C, and that the oxidation increment of SiCp and the thickness of SiO2 layer increase with the increase in pre-oxidation temperature and time, when the oxidized temperature exceeds 1100 degrees C, or the duration time exceeds 2h at 1100 degrees C, a small amount of ablation will take place on the SiCp, as well as the oxidized layer has some loss. The formation of SiO2 layer can provide certain interface reactions with interface layers (3.16.36m), and the higher the thickness of SiO2 layer, the thicker the interface layer in SiCp/Al composites. However, the thickness of SiO2 layer is more than 5.9m, which is not benefit for the formation of interface layer. With the increase in the thickness of interface layer, thermal conductivity declines, but is not linear.