Carbon fiber reinforced Si-C-N matrix composite with a Si-O-C interphase (C/Si-O-C/Si-C-N) was fabricated via chemical vapor infiltration and polymer impregnation and pyrolysis process. The mechanical properties and oxidation behaviors of C/Si-O-C/Si-C-N were investigated using three-point-bending test and thermogravimetry. The results indicated that the oxidation resistance of C/Si-O-C/Si-C-N was improved as compared to C/Si-C-N with pyrolytic carbon (PyC) interphase (C/PyC/Si-C-N). The higher oxidation resistance of C/Si-O-C/Si-C-N attributed to the high inoxidizability of Si-O-C interlayer and low thermal stress in matrix. The flexural strength of C/Si-O-C/Si-C-N rivaled that of C/PyC/Si-C-N and the modulus was higher than that of C/PyC/Si-C-N. The suitable interphase and the optimized interface bonding can get the high oxidation resistance of the composites with the mechanical properties maintained.