Carbon fiber reinforced SiBCN鄄matrix composites were fabricated by polymer infiltration and pyrolysis route (PIP) with a lab鄄produced SiBCN precursor (P鄄SiBCN) as a matrix source. Their mechanical properties were investigated. The composite obtained from 8 PIP鄄cycles showed its flexure strengths of 334 MPa at room temperature, and in鄄situ flexure strength of 367 MPa at 800益in inert gas atmosphere. The composite retained its 60% strengths upon bending even at 800益in air.