$eta$-Sialon powder was prepared by the reduction-nitridation reaction from the mixture of Wando Pyrophyllite and carbon black at 135$0^{circ}C$ in $N_2$ atmosphere. $eta$-SiC powder was added to the prepared $eta$-Sialon powder to make $eta$-Sialon-SiC composite. The $eta$-Sialon-SiC composites were sintered pressurelessly at 175$0^{circ}C$ for 2h, using $Y_2O_3$ and $ZrO_2$(monoclinic) as sintering aids. Comparatively higher values of the fracture toughness (3.8 MN/㎥/2), M.O.R. (470 MN/$m^2$) and vickers microhardness (13.7 MN/$m^2$) were obtained when 10 wt% $Y_2O_3$ was added as a sintering aid. The improved fracture toughness and M.O.R. are assumed to be the results of crack deflection and crack branching by the second phase SiC particles.