In this paper, green bodies of RBSC were prepared through the gel-casting process. The effects of monomer concentration and ratio of MBAM to AM on the strength and microstructure of the green bodies were studied. When the monomer content increased from 10wt% to 20wt %( relative to water in the slurry), the flexural strength increases efficiency. However, the flexural strength decreases when the monomer content was above 20wt%. Similarly, when the ratio of MBAM to AM increased from 1/19 to 1/9, it had the same effects on the flexural strength of green bodies. It was found that silicon carbide particles were packaged by the carbon particles with gel. When the monomer content was 20wt% and the ratio of MBAM to AM was 1/9, the green body showed the best homogeneous microstructures and its flexural strength achieved 8MPa.