Abstract: The effects of nano-SiC power additive on rheological behavior of SiC slurry and mechanical properties of RBSC were investigated. SiC blanks were prepared with gel-casting method, through drying, burning out the organic elements, infiltrating silicon and reaction sintering, the RBSC with nano-SiC particles were fabricated. Influence of solid loading, ball-milling time and nano-SiC particles on rheological behavior of SiC slurry was discussed. Due to the addition of nano-SiC particles, SiC slurry rheological behavior was changed from shear thinning to first shear thickening, then shear thinning. With 7% nano-SiC powder, the bending strength and elastic modulus of RBSC were elevated to 345 MPa and 339 GPa,respectively increasing by 18.1% and 13.8%. RBSC mechanical properties were improved with the addition of nano-SiC powder.