The mechanical and electrical properties of hot-pressed and annelaed $eta$-SiC+39vol.% $ZrB_2$ electroconductive ceramic composites were investigated as a function of the liquid forming additives of $Al_2O_3+Y_2O_3$(6:4 wt%). In this microstructures, no reactions and elongated $alpha$-SiC grains with equiaxed $ZrB_2$ grains were observed between $eta$-SiC and $ZrB_2$. The properties of the $eta$-SiC+39vol.%$ZrB_2$ composites with 4wt% $Al_2O_3+Y_2O_3$ at R.T. are as follows: fracture toughness is 6.37 MPa.m1/2, electical resistivity is $1.51 imes10^{-4}Omega cdot extrm{cm}$ and the relative density is 98.6% of the theoretical density. The fracture toughness of the $eta$-SiC+39 vol.% $ZrB_2$ composites were weakly decreased with increasing amount of $Al_2O_3+Y_2O_3$ additives. Internal stresses due to the difference of $eta$-SiC and $ZrB_2$ thermal expansion coefficient and elastic modulus mismatch appeared to contribute to fracture toughening in $eta$-SiC+39vol.%$ZrB_2$ electroconductive ceramic composites.