C/SiC composites were manufactured by the process of reactive infiltration of gaseous silicon with carbon felt reinforced carbon green, which is made from viscose rayon-based carbon felt perform treated with CVD carbon and phenolic resin pyrolysis carbon. Effects of re-impregnation and pyrolysis cycles of resin on the density and porosities of green and the micrograph and mechanical properties of C/SiC were studied. The result indicates that with the increase of re-impregnation cycles and the density of green, the porosities of green declines. The bending strength and modulus of C/SiC reach the maximal figures, respectively 231MPa and 209GPa when the pyrolysis carbon content of preform is set to 27wt%. The mechanical and microstructure properties of C/SiC can be tailored by controlling the pyrolysis carbon volume in the green.