A suitable SiBCN ceramic precursor was prepared by combining a high-viscosity polyborosilazane and a low-viscosity polysilazane. Its chemical structures were analyzed by FT-IR spectra. The thermal behavior of precursor was characterized by rheological dynamic analysis (RDA) and differential scanning calorimetry (DSC), and the thermal properties of the corresponding ceramic product were investigated under air or argon over the temperature range of 25-1500°C. Then, carbon fiber-reinforced SiBCN ceramic matrix composites (CMCs) were prepared via infiltration of fiber preforms using the polymer infiltration technique and polymer pyrolysis. Mechanical properties of the ceramic matrix composite were evaluated and the microstructures of the obtained composites were investigated by SEM.