C/SiC composites fabricated by precursor infiltration pyrolysis process are prone to oxidation above 400℃. Their oxidation behaviors have been researched on. The oxidation loss of C fiber textiles or C/SiC composites without coating increases at 400℃ to 1300℃. However,the oxidation loss of C/SiC composites with CVD-SiC coating or three-layer coating, respectively CVD-SiC layer, self-sealing layer and CVD-SiC layer, at first increases at 500℃ to 700℃, then decreases at 800～1300℃. Oxidation loss of C/SiC composites with three-layer coating are less than 6.4% at 800～1300℃ for 288h.SEM photographs indicate vitreous self-sealing layer filling in cracks.