C/ZrC composites were prepared via reactive melt infiltration with zirconium from porous C/C preforms with various pyrocarbon contents. As the pyrocarbon amount in C/C preform increased from 34.1vol.% to 61.7vol.%, the densification of C/ZrC composites was hindered and the ZrC content in C/ZrC composites decreased gradually from 35.3vol.% to 6.3vol.%. Meanwhile, the flexural strength of C/ZrC composites decreased initially and then increased, but the flexural modulus rose continuously. The flexural strength and modulus of the composites fabricated from the preform with 34.1 vol.% pyrocarbon matrix were 181±4MPa and 13.0±1.2GPa, respectively, and the mass loss rate and linear recession rate were 0.0031g/s and 0.0012mm/s, respectively.