Effect of starting SiC particle size on nitridation rate and flexural strength of $Si_3N_4$-bonded-SiC (SNBSC) ceramics was investigated by using SiC particles of different size (${sim}200;{mu}m$, ${sim}100;{mu}m$ and ${sim}45;{mu}m$). The specimen prepared from smaller SiC particles resulted in higher nitridation rate after nitridation at $1450^{circ}C$, owing to the lower packing density in green body. The flexural strength showed maxima after 1-h nitridation for all specimens and then decreased with prolonged nitridation because of local densification-induced pore coarsening. The specimen prepared from smaller SiC particles showed better flexural strength because of smaller pore size and partly higher nitridation rate in the specimen. A maximal flexural strength of 29 MPa was obtained in the specimen with a density of $2.04;g{cdot}cm^3$, which was prepared from $45;{mu}m$-SiC particles.